Ecclesiology is the study of the origin, nature, structure, and mission of the Church, corresponding to the four causes: efficient, formal, material, and final. Drawing upon the sources of theology, ecclesiology seeks to obtain and to communicate an understanding of the Church as a theological object, that is, as something related to and revealed by the Triune God. In dogmatic or systematic theology, such understanding includes an exposition of the relationship between various revealed mysteries of the faith to one another, showing how one mystery sheds light on another or how two or more mysteries are mutually illuminating (Cuddy 2024, IV). It is to this latter aspect, as a subspecialty within dogmatic theology, that “eucharistic ecclesiology” corresponds.

As the term itself suggests, eucharistic ecclesiology explains the mystery of the Church in light of the Church’s close relationship to the sacrament of the Most Holy Eucharist. Thus, eucharistic ecclesiology discusses ways in which the Church’s origin, nature, structure, and mission are connected to the Eucharist or, more broadly, how the two mysteries—the Church and the Eucharist—are intimately bound together.

Since all of the mysteries of faith constitute one overarching mystery, and because each mystery is in some way tied to other mysteries, eucharistic ecclesiology does not discuss the Church’s eucharistic character in complete isolation from other mysteries of the faith. Eucharistic ecclesiology inevitably connects to other areas of theology, including—but not limited to—trinitarian theology, Christology, soteriology, and eschatology. The Eucharist is a sacrament, so sacramental theology also has its place within eucharistic ecclesiology.

What identifies this subspeciality as eucharistic ecclesiology is the emphasis placed on the role of the Eucharist within the nexus of these other mysteries in their shared connection to the mystery of the Church. Eucharistic ecclesiology is thus a branch of—or approach to—ecclesiology that strongly underscores the Church-Eucharist relation.

Eucharistic ecclesiology is also used at times as a synonym for “communion ecclesiology” for reasons that will become evident in due course. Alternatively, eucharistic ecclesiology can also be considered a species within the genus of communion ecclesiology.

Eucharistic ecclesiology is not the only approach to Catholic ecclesiology. It would be erroneous to think that any given ecclesiological treatise that does not explicitly highlight the eucharistic dimension is, ipso facto, false. Nevertheless, it must be said that the Church-Eucharist relation is a reality which this branch of theological science seeks to elaborate. Eucharistic ecclesiology, therefore, is not merely a helpful hermeneutic or an arbitrary conceptual tool. It investigates the truth of the Church in her real connection to the Eucharist, a constitutive element of her essence, existence, and purpose.

Historically, the term “eucharistic ecclesiology’” was coined by Nicholas (or Nicolas) Afanasiev (a.k.a. Nikolay Afanassieff) (1893–1966), a Russian Orthodox scholar who taught in Paris (McPartlan 2008, 326). Although the phrase was first employed in the twentieth century, Afanasiev used it to describe the ecclesiology of the early Church. His work inspired other theologians from various Churches and ecclesial communities to explore the same theme, albeit in ways that often depart from some of Afanasiev’s own views on particular, important points (see Wooden, Recovering).

Other notable theologians known for their work in eucharistic ecclesiology include the Greek Orthodox Metropolitan of Pergamon, John Zizioulas (1931–2023), the Russian Orthodox theologians George Florovsky (1893–1979) and Olivier Clément (1921–2009), and—on the Catholic side—Henri de Lubac (1896–1991), Jean-Marie Roger Tillard (1927–2000), and Joseph Ratzinger/Benedict XVI (1927–2022). For his part, Zizioulas served as co-chair or co-president of the Joint International Commission for the Theological Dialogue between the Catholic Church and the Orthodox Church (as a whole) alongside Cardinal Walter Kasper (b. 1933) and, at a separate time, Cardinal Kurt Koch (b. 1950). Given his history within Catholic-Orthodox dialogue, Zizioulas will serve as the primary representative of Orthodox thought here, but the reader should be aware that not every Orthodox theologian agrees with him on every point.

Within the Catholic academy, eucharistic ecclesiology is usually associated with the ressourcement movement and its adjacent projects. However, key elements and principles of this ecclesiology can be found in the thought of St. Thomas Aquinas (1225–1274) and in the work of those associated with modern and contemporary Thomism. A few Thomist works will be drawn from accordingly. This approach will show that, in its substance, eucharistic ecclesiology is not the recent invention of a “new theology” but rather explicates anew perennial theological teaching.

In what follows, eucharistic ecclesiology will be considered in light of those facets of ecclesiology mentioned earlier: origin, nature, structure, and mission. Each will be treated in that order, although some overlap is inevitable and even desirable. Various theological sources will be drawn upon, from Scripture to the present day. Hopefully, this procedure will help the reader to see that eucharistic ecclesiology is rooted in divine revelation itself and has been part of Catholic doctrine and theology in every age, sometimes more implicitly than explicitly but no less authentically. Additionally, in light of the significant attention eucharistic ecclesiology has been given in ecumenical dialogues over the last several decades, it is appropriate that occasional references will be made to ecumenical texts.

I. Origin of the Church

The Church’s origin is divine. That is to say, she was established by God as part of the plan of salvation. As the Second Vatican Council teaches:

[The Father] planned to assemble in the holy Church all those who would believe in Christ. Already from the beginning of the world the foreshadowing of the Church took place. It was prepared in a remarkable way throughout the history of the people of Israel and by means of the Old Covenant. In the present era of time the Church was constituted and, by the outpouring of the Holy Spirit, was made manifest. At the end of time it will gloriously achieve completion, when . . . all the just . . . will be gathered together with the Father in the universal Church. (Lumen gentium, no. 2)

In particular, the Church was instituted by Christ Himself (see Mt 16:18; CCC nos. 763–766, 771), especially through His Paschal Mystery. “The Church is born primarily of Christ’s total self-giving for our salvation, anticipated in the institution of the Eucharist and fulfilled on the cross” (CCC, no. 766). “For it was from the side of Christ as He slept the sleep of death upon the cross that there came forth ‘the wonderous sacrament of the whole Church’” (Sacrosanctum concilium, no. 5; see CCC, no. 766).

Here, the Second Vatican Council harkens back to a Patristic reading of John 19:34. As Pope Benedict XVI explains: “The Fathers of the Church often meditated on the relationship between Eve’s coming forth from the side of Adam as he slept (cf. Gn 2:21–23) and the coming forth of the new Eve, the Church, from the open side of Christ sleeping in death: from Christ’s pierced side, John recounts, there came forth blood and water (cf. Jn 19:34), the symbol of the sacraments,” which “leads us to reflect on the causal connection between Christ’s sacrifice, the Eucharist and the Church” (Sacramentum caritatis, no. 14).

Pope Benedict’s mention of causality in reference to Christ’s Passion, the Eucharist, and the Church connects well to the theme of Christ’s headship (or capital grace), which links together Christology, soteriology, sacramental theology, and ecclesiology. As St. Thomas Aquinas teaches, “grace was bestowed upon Christ, not only as an individual, but inasmuch as He is Head of the Church, so that it might overflow into His members. . . . Christ by His Passion merited salvation, not only for Himself, but likewise for all His members” (ST III, q. 48, a. 1). The merit of salvation is objectively accomplished for all through Christ’s Passion, but “Christ’s Passion is, so to say, applied to man through the Sacraments” (ST III, q. 61, a. 1, ad 3). It is through the sacraments that men become members of the body of Christ. “For,” as Aquinas states, “it is evident that through the sacraments of the New Law man is incorporated into Christ” (STIII, q. 62., a. 1, resp.).

The incorporation of men into Christ brings them also into unity with one another, making them members of the Church with Christ himself as the head. Hence, the Church’s origin is found in the communication of Christ’s grace to humanity, a theme of profound importance to St. Thomas. As Jean-Pierre Torrell, O.P. (b. 1927), comments on the Summa theologiae: “This communication of the grace of Christ to men, which gives birth to the mystical body of Christ, that is to say the Church, is for Thomas a subject of so great importance that he preferred to treat it separately from the other problems tied to the grace of Christ and has reserved an entire question for it [i.e., ST III, q. 8]” (Torrell in Aquinas, Somme théologique, 325; translation my own).

The formation of the Church through the sacraments is especially true of the Eucharist. St. Paul is explicit about this fact: “The cup of blessing which we bless, is it not a communion in the blood of Christ? The bread that we break, is it not a communion in the body of Christ? Because there is one bread, we who are many are one body, for we all partake of the one bread” (1 Cor 10:16–17). Essentially, St. Paul is insisting that the reception of the Eucharist effects the communion of the Church’s members as one. By receiving the body of Christ, we become the body of Christ.

This biblical teaching has been affirmed and transmitted throughout the ages by Fathers of the Church, medieval scholastics, and magisterial documents. This fact is succinctly demonstrated in Pope Leo XIII’s encyclical, Mirae caritatis, where he quotes St. Cyprian of Carthage, St. Augustine, and St. Thomas Aquinas on the connection between the Eucharist and the bonds of ecclesial communion (see Denzinger, no. 3362). Leo teaches that “the outward and visible elements of this sacrament supply a singularly appropriate stimulus to union. On this topic St. Cyprian writes: ‘ . . . For when our Lord calls his body bread, a substance that is kneaded together out of many grains, he indicates that we his people, whom he sustains, are bound together in close union. . . . we his flock are by the commingling of a multitude of persons made one’” (Mirae caritatis, no. 11.). Continuing, Leo notes: “In like manner the Angelic Doctor, adopting the sentiments of St. Augustine, writes: ‘Our Lord has bequeathed to us his body and blood in (the form of) these elements in which a multitude of things have been reduced to unity, for one of them, namely, bread, consisting as it does of many grains is yet one, and the other, that is to say, wine, has its unity of being from the confluent juice of many grapes, and therefore St. Augustine elsewhere says: “O Sacrament of mercy, O sign of unity, O bond of charity!”‘“ (Mirae caritatis, no. 11; see ST III, q. 79, a. 1).

Emmanuel Doronzo, O.M.I. (1903–1976), a Thomistic sacramental theologian who taught at the Catholic University of America, also remarks on the great host of Patristic passages that speak of the symbolism of the elements used in the Eucharist which express ecclesial communion: “In many ways, the Fathers extol and explain the same effect of mystical union, whether with Christ or with his members in him, insisting particularly on the aforementioned Eucharistic symbolism of bread and wine, to which they add the symbolism of consecrating an admixture of water with wine” (Doronzo, De Eucharistia, 459, translation my own). About the mixture of water and wine, St. Cyprian writes: “… we see that in the water is understood the people, but in the wine is showed the blood of Christ. But when the water is mingled in the cup with wine, the people is made one with Christ, and the assembly of believers is associated and conjoined with Him on whom it believes” (Epistle 62, 13).

It is this unifying effect that gives the Eucharist its other name: communion. As St. Thomas Aquinas writes about the Eucharist: “[St. John] Damascene says (De Fide Orthod. iv) that it is called Communion because we communicate with Christ through it, both because we partake of His flesh and Godhead, and because we communicate with and are united to one another through it” (ST III, q. 73, a. 4). Thus, Aquinas declares that this sacrament, the Eucharist, “has another meaning, namely, that of Ecclesiastical unity, in which men are aggregated through this Sacrament; and in this respect it is called Communion” (ST III, q. 73, a. 4). Here, Aquinas confirms what he had already said in the previous article: “the reality [res tantum] of the sacrament [of the Eucharist] is the unity of the mystical body,” the Church (ST III, q. 73, a. 3). Notably, Tillard explicitly recognizes the presence of this eucharistic ecclesiological principle in Aquinas, citing this very passage (Tillard 1983, 53).

In its Decree on the Sacrament of the Eucharist, the Council of Trent speaks of “that very Eucharist which our Savior left in his Church precisely as a symbol of the unity and charity with which he wished all Christians to be joined together and united with each other” (Denzinger 2012, no. 1635).

Pope St. John Paul II (1920–2005) also connects the Church’s origin to the Eucharist: “By the gift of the Holy Spirit at Pentecost the Church was born and set out upon the pathways of the world, yet a decisive moment in her taking shape was certainly the institution of the Eucharist in the Upper Room. Her foundation and wellspring is the whole Triduum paschale, but this is as it were gathered up, foreshadowed and ‘concentrated’ for ever [sic] in the gift of the Eucharist” (Ecclesia de Eucharistia no. 5). For, as he also says, “the Eucharist . . . is in an outstanding way the sacrament of the paschal mystery” (Ecclesia de Eucharistia, no. 3). If Pentecost is frequently discussed as the birth of the Church, the institution of the Eucharist on Holy Thursday can be viewed as her conception.

The Eucharist not only stands at the institution of the Church but also functions as a fundamental means of sustaining her throughout time and of causing her growth. After all, it is not only the disciples in the Upper Room that form the Church through the Holy Eucharist. Rather, all those who are initiated into the Church via Baptism, Chrismation, and Holy Communion are likewise incorporated into the mystical body of Christ.

In the early twentieth century, Henri de Lubac was one of the foremost Catholic theologians to reinvigorate the profound understanding of this intrinsic link between the Church and the Eucharist. In his book, Corpus Mysticum: The Eucharist and the Church in the Middle Ages, de Lubac pursues a lengthy study of the history of the use of the term “corpus mysticum.” At the risk of oversimplifying, de Lubac contends that prior to the controversy stemming from the work of Berengar of Tours (d. 1088), many authors used “corpus mysticum” in reference to the body of Christ in the sacrament of the Eucharist. The need to emphasize the reality of Christ’s presence in the Eucharist in the face of Berengar’s heresy led to a terminological shift in emphasis to “corpus verum” to discuss the Eucharist. The term “corpus mysticum” became more frequently applied to the Church. Unfortunately, in de Lubac’s view, this terminological shift often included an inappropriate sense of opposition between true and mystical, as if that which is mystical is not real. Concomitantly, the intrinsic link between the Eucharist as the body of Christ and the Church as the body of Christ became less and less emphasized. Thus, along with his study of the terminology, de Lubac wished to once again call to the fore the relation between the Eucharist and the Church (see de Lubac, Corpus Mysticum). As Joseph Ratzinger remarks: “Henri de Lubac in a splendid work of extensive scholarship made clear that the term corpus mysticum originally designated the most Holy Eucharist and that for Paul, as well as the Church Fathers, the notion of the Church as the body of Christ was inseparably bound to the notion of the Eucharist in which the Lord is bodily present and gives us his body to eat” (Ratzinger 1988, 242). In relation to the question of the origins of the Church, Paul McPartlan (b. 1955) speaks of “the celebrated double principle coined by de Lubac, that ‘the Church makes the Eucharist’ and ‘the Eucharist makes the Church’” (McPartlan 2006, xvii). The Church and the Eucharist are mutually constitutive.

Here, we shall focus on the second idea, namely, that the Eucharist makes the Church, a phrase which now appears in the Catechism (no. 1396). The Thomistic ecclesiologist Charles Cardinal Journet (1891–1975) explains this notion by a kind of inverse analogy between eating regular food and eating the bread of life: “The union of Christians to Christ is symbolized by the union of assimilation, that is to say, by the strongest union visible reality can offer. But there is a reversal here: material nutrition, which is inanimate, causes life only by being assimilated; while the Bread of which we now speak is Life and gives life by assimilating: ‘He who eats me will live because of me’ (Jn 6:57)” (Journet 2004, 181). This explication is reminiscent of the words that St. Augustine places in the mouth of Jesus: “‘[Y]ou shall feed upon me. You will not change me into yourself, as you change food into your flesh, but you will be changed into me’” (Confessions, VII, 10). Being turned into Christ means, of course, that the communicants are incorporated into the body of Christ, the Church, and vivified with His sanctifying power.

Journet further explains how ecclesial communion arises from the Eucharist: “[T]he grace that the Eucharist bestows,” he writes, is “perfect charity, from which results the unity of Christ’s Mystical Body” (Theology of the Church, 182). “Unity is the result of love, and the exceptional unity of the Church is the result of the exceptional love that the Holy Spirit communicates to men through contact with Christ. This exceptional love . . . is, by means of the Eucharist, communicated under its holiest and highest form, one that is most suitable to conform one to Christ” (Theology of the Church, 183). For this reason, Aquinas says, “the Eucharist is termed the sacrament of Charity, which is the bond of perfection (Col. 3:14)” (ST III, q. 73, a. 3, ad 3; see also Benedict XVI, Sacramentum caritatis, no. 1).

It is fitting to highlight why the bonds of charity are so important for the Church and hence why the virtue of charity bestowed by the Eucharist is essential. After highlighting the unity of faith as an aspect of the Church, Louis Cardinal Billot, S.J. (1846–1931), a renowned scholastic theologian and ecclesiologist, explains why unity of faith is necessary but not sufficient. He writes: “when Christ now asks from the Father what he wants to be the reward of the merits of his death—undoubtedly the complete and absolute unity of his Church—it is not to be understood as the unity of faith alone but also the unity of communion, without which unity (properly so called [veri nominis]) amongst the multitude of men cannot be conceived. For men are united not only by the union of intellects, but most of all by the cohesion of wills” (Billot 1909, 157; translation my own). Billot thus equates “unity of communion” with “unity of wills,” which—in the order of grace—comprises the supernatural bond of love (the theological virtue of charity). The faithful are united together in their love and adoration of almighty God through the eucharistic sacrifice, and they receive the grace of charity through the reception of Holy Communion, which binds them together.

The view that the Eucharist builds up the Church is shared by Catholics and Orthodox. In 1982, the Joint International Commission for Theological Dialogue between the Catholic Church and the Orthodox Church (as a whole) issued a document which states: “the eucharist builds up the church in the sense that through it the Spirit of the risen Christ fashions the church into the body of Christ. That is why the eucharist is truly the sacrament of the church” (“The Mystery of the Church,” no. 4c).

Indeed, eucharistic ecclesiology has arguably been the most helpful approach for advancing Catholic-Orthodox dialogue. As John Zizioulas said to the 2005 Synod of (Catholic) Bishops: “There may still be things that separate our two Churches, but we both believe that the Eucharist is the heart of the Church. It is on this basis that we can continue the official theological dialogue. . . . Eucharistic ecclesiology can guide us in our efforts to overcome 1000 years of separation. . . . The Eucharist belongs not simply to the well-being but to the being of the Church. The whole life, word and structure of the Church is Eucharistic in its very essence” (quoted from McPartlan, “Catholic Learning,” 160).

Although there is less commonality between, on the one hand, Catholic and Orthodox understandings of the Church and of the Eucharist and, on the other, Protestant understandings, some progress has nevertheless been made on this issue in broader ecumenical endeavors. In a 1982 document, the Faith and Order Commission of the World Council of Churches states: “The eucharistic communion with Christ who nourishes the life of the Church is at the same time communion with the body of Christ which is the Church” (World Council of Churches 1982, 12). Accordingly, eucharistic ecclesiology is proving to be a fruitful avenue for improved ecumenical relations between a variety of Christian Churches and ecclesial communities.

The above comments on the origin of the Church already intimate and lead to a consideration of the Church’s nature, to which we now turn.

II. The Nature of the Church

The New Testament Greek term for Church is ekklesia, which is used in the Septuagint to translate the Semitic word qahal, which means ‘assembly of the people,’ or, more specifically, ‘the community of Yahweh.’ As Christopher Ruddy explains, “the qahal has its roots in the covenant formed by the promulgation of the Law at Sinai. It is thus a ‘people of the covenant,’ created by a divine call or initiative, and set apart in holiness” (Ruddy 2006, 57).

After the Diaspora, the Jewish people began to pray that God would bring about a new gathering of his people, a new qahal. According to Ratzinger, “It is thus clear what it means for the nascent Church to call herself ecclesia. By doing so, she says in effect: This petition is granted in us. Christ, who died and rose again, is the living Sinai; those who approach him are the chosen final gathering of God’s people (cf., for example, Heb 12:18–24)” (Called to Communion, 31). The Church, then, is the people of God, the communion of those whom God has gathered to himself in Christ (see Lumen gentium, Ch. II).

There are many images of the Church that bespeak the essence of the Church as communion. In addition to “people of God,” Lumen gentium enumerates several other biblical metaphors for this communion: kingdom of God, sheepfold, house or household of God, holy temple (made of many stones), holy city (new Jerusalem), bride of Christ (see no. 6), and, of course, body of Christ (see no. 7). All of these evoke the idea of many (people or components) forming a single unity.

For his part, Ratzinger links the last two images mentioned: body and bride. “The Church is the Body, not by virtue of an identity without distinction, but rather by means of the pneumatic-real act of spousal love. . . . this means that Christ and the Church are one body in the sense in which man and woman are one flesh, that is, in such a way that in their indissoluble spiritual-bodily union, they nonetheless remain unconfused and unmingled” (Ratzinger, Called to Communion, 39). The Church is the body of Christ as the bride of Christ. The two form a unity but one in which they do not lose their distinct identities. It is a communion of persons that form a single whole.

In this way, the Church’s essence or nature reflects her divine, trinitarian origin. As Ratzinger writes, “belief in the Trinity is communio; to believe in the Trinity is to become communio. . . . the oneness of the believing subject [the Church] is the necessary counterpart and consequence of the known ‘object,’ [the triune God]” (Ratzinger 1987, 23). That last phrase, “consequence of the known object” basically points to the fact that the Church as communion results from a share in the communal life of the Trinity.

As the Catechism teaches, connecting the Church’s divine origin to the Church’s nature: “The Church is one because of her source: ‘the highest exemplar and source of this mystery is the unity, in the Trinity of Persons, of one God, the Father and the Son and the Holy Spirit.’ . . . Unity is of the essence of the Church” (no. 813, quoting Unitatis redintegratio, no. 2).

This trinitarian dimension of ecclesial communion is most effective in the Eucharist. As the international Catholic-Orthodox dialogue states: “The Spirit puts into communion with the body of Christ those who share the same bread and the same cup. Starting from there, the church manifests what it is, the sacrament of the Trinitarian koinonia[communion]” (“The Mystery of the Church,” no. 5d). It continues: “Taken as a whole, the eucharistic celebration makes present the Trinitarian mystery of the church” (“The Mystery of the Church,” no. 6).

Thomistic theologian Benoît-Dominique de la Soujeole, O.P. (b. 1955), approves of “the modern rediscovery of communion as a definition of the Church. Communion is the name of the unity that charity effects. Thomas has left us a profound theology of charity as friendship (ST II-II, q. 23, a. 1), that is, reciprocal love founded on a common good. . . . he transposed it [from Aristotle] to the level of the marvelous New Testament concept of koinonia [communion]: God shares His beatitude with us so that we might share in it; thence is born community between God and human beings” (de la Soujeole 2010, 832).

The Church, in her essence, is a communion containing two dimensions: the vertical dimension of communion of humanity with God and the horizontal communion between the members of the Church, the latter being rooted in the former. As Ratzinger puts it: “The Church is the dynamic process of horizontal and vertical unification. It is vertical unification, which brings about the union of man with the triune love of God, thus also integrating man in and with himself. . . . Only by the impulse power of vertical unification can horizontal unification, by which I mean the coming together of divided humanity, also successfully take place” (Ratzinger 1966, 76).

The Church signifies and effects the communion between God and humanity as well as the communion within humanity that results, and, hence, can be understood as a sacrament. As de la Soujeole notes: “Thomas establishes that a sacrament ‘contains’ the grace which it confers” (Soujeole 2010, 829). As the Catechism teaches, quoting Lumen gentium, no. 1: “‘The Church, in Christ, is like a sacrament—a sign and instrument, that is, of communion with God and of unity among all men.’ The Church’s first purpose is to be the sacrament of the inner union of men with God. Because men’s communion with one another is rooted in that union with God, the Church is also the sacrament of the unity of the human race” (CCC, no. 775).

As already seen in the prior section, the Eucharist is an instrumental cause of this two-fold communion. “Really partaking of the body of the Lord in the breaking of the Eucharistic bread, we are taken up into communion with Him and with one another. . . . In this way all of us are made members of His Body, ‘but severally members of one another’” (Lumen gentium no. 7, quoting Rom 12:5). Following Ruddy’s remark that the Church is the “people of the Covenant,” it is helpful to recall that, at the Last Supper, Jesus declares that the cup is the new covenant in his blood (see Lk 22:20). The Eucharist, then, is the sacrament par excellence of the new covenant establishing the people of God.

Accordingly, the Church can be seen primarily and essentially as the eucharistic assembly, that is, the unity of the members gathered together to offer the Eucharist to the Father through Christ in the Holy Spirit. In fact, the majority of times the word ‘church’ (ekklesia) is used in the New Testament, it bears that connotation. After noting that approximately 70% of New Testament uses of “ekklesia” refer to a local assembly, Zizioulas writes: “The point of altogether special importance is that it was not just any assembly, but strictly speaking, the eucharistic assembly that was called ekklesia of ‘Church’” (Zizioulas 2001, 46).

Such usage of the term “church” continued in the Patristic era. As Ratzinger notes: “According to the Fathers, Eucharist and Church do not stand as two different things next to one another but fall thoroughly into one another” (Ratzinger, 1980, 32, translation my own). Elsewhere, he says: “The Church lives in eucharistic communities” (Ratzinger 1986, 243). Accordingly, Lumen gentium, no. 11 teaches: “Taking part in the Eucharistic sacrifice . . . is the source and summit [or, fount and apex] of the whole Christian life.” As Ratzinger phrases it: “In the Eucharist, the Church is most compactly herself” (Ratzinger 1966, 37).

Indeed, the Eucharist is so essential to the Church that the Second Vatican Council and post-conciliar magisterial texts make a distinction between Churches and ecclesial communities. With regard to the latter, the Congregation for the Doctrine of the Faith (CDF) writes that “ecclesial Communities which, specifically because of the absence of the sacramental priesthood, have not preserved the genuine and integral substance of the Eucharistic Mystery cannot, according to Catholic doctrine, be called ‘Churches’ in the proper sense” (CDF, “Response”). Notice that the emphasis is on the fact that ecclesial communities have not preserved the Eucharist and hence cannot be called Churches; the loss of sacramental priesthood is mentioned because it is a necessary condition for the valid consecration of the Eucharist, but the loss of the Eucharist itself is the primary reason given for the doctrinal conclusion.

This CDF document cites two other magisterial texts in support of this teaching. Vatican II’s Decree on Ecumenism, Unitatis redintegratio, describes ecclesial communities by noting that “they have not retained the proper reality of the eucharistic mystery in its fullness, especially because of the absence of the sacrament of Orders” (no. 22). Similarly, the CDF document, Dominus Iesus states that “ecclesial communities which have not preserved the valid Episcopate and the genuine and integral substance of the Eucharistic mystery, are not Churches in the proper sense” (no. 17). Conversely, while insisting that “there exists a single Church of Christ, which subsists in the Catholic Church,” the CDF acknowledges that the “Churches which, while not existing in perfect communion with the Catholic Church, remain united to her by means of the closest bonds, that is, by apostolic succession and a valid Eucharist, are true particular Churches” (no. 17). The Eucharist belongs to the very essence of the Church. Without the ability to celebrate the Eucharist validly, there is no Church in the full theological and doctrinal meaning of the term.

Because the Eucharist is essential to the Church, it relates to the four marks of the Church enumerated in the Nicene Creed: one, holy, catholic, and apostolic (see DeClue, “The Eucharist”). As that which unifies the members of the Church, the Eucharist is obviously linked to the Church’s unity (oneness). By bestowing sanctifying grace—especially the theological virtue of charity (as discussed above)—the Eucharist effects the holiness of the Church and her members. As Ruddy explains: “life in Christ begun by baptism reaches its earthly climax in the eucharist. . . . the eucharist is a present sharing in divine communion that anticipates the believer’s perfect holiness” (Ruddy 2006, 65). We shall see, especially in the following section on Church structure, that the Eucharist is also connected to the catholicity and apostolicity of the Church.

In the meantime, the Catechism offers some comments that help bridge the gap between this discussion of the Church’s nature and the consideration of ecclesial structure to follow. The Catechism offers three senses of the word “Church,” the first of which is eucharistic. “In Christian usage, the word ‘church’ designates the liturgical assembly. . . . She exists in local communities and is made real as a liturgical, above all a Eucharistic, assembly. She draws her life from the word and the Body of Christ and so herself becomes Christ’s Body” (no. 752, emphasis added). Importantly, the Catechism specifies that this eucharistic dimension is bound up with the other meanings of “Church.” The Church is “also the local community or the whole universal community of believers. These three meanings are inseparable” (no. 752.). This teaching leads to our next topic: the structure of the Church.

III. The Structure of the Church

As noted above, the term “Church” is multivalent. It can refer to the eucharistic assembly, the local or particular church (i.e., diocese or eparchy), or the universal Church. These three, as already stated, are tied to one another.

This section aims to show how Church structure is related to the Eucharist. It will consider the Church as both local and universal. It will also treat ecclesial hierarchy in relation to the Eucharist, including the role of the bishop; episcopal collegiality; and universal primacy. Together and interrelatedly, these considerations will show how the Eucharist is linked to the remaining two marks of the Church: catholicity and apostolicity.

As regards the Church’s locality and universality, various theologians emphasize one or the other. Orthodox theologians tend to emphasize the local/particular church. Afanasiev perhaps holds the most extreme version of this view. He “so stresses the self-sufficiency of the local church as to minimize or even deny the necessity of larger connections” (Doyle 2000, 160). Zizioulas has a more moderate view. While he emphasizes the local church, Zizioulas affirms (contra Afanasiev) the need for local churches to maintain universal communion, and for eucharistic reasons. “I have always believed,” he writes, “that the nature of the Eucharist points to the simultaneity of locality and universality in ecclesiology” (Zizioulas 1999, 119).

Ratzinger is perhaps the prime example of a Catholic eucharistic ecclesiologist who emphasizes the priority of the universal Church. His view will be discussed later. Walter Kasper (b. 1933) is a Catholic theologian who famously criticized Ratzinger and the CDF on that point (see “Zur Theologie”), leading to an exchange between the two German scholars famously called the “Ratzinger-Kasper Debate.” Overall, Kasper’s position is between that of Ratzinger and Zizioulas, putting the local church and universal Church on equal footing (see Kasper, “On the Church”). In what follows, agreements and disagreements between Zizioulas, Ratzinger, Kasper, and Tillard will be mentioned, although not exhaustively.

First, all four agree on what can be called the full ecclesial quality of the local church. (Here, “local church” or, more technically, “particular church,” refers to the diocese or eparchy, not the parish, for reasons to be discussed later.) Referring to St. Ignatius of Antioch, Zizioulas writes: “What characterizes Ignatius in particular is that for him the Eucharist does not simply make the local community into the Church, but that it makes it the catholic Church . . . i.e. the full and integral body of Christ” (Zizioulas 1982, 335). Zizioulas interprets the Greek katholou (catholic) in a qualitative sense, “denoting what is full, whole, general, or common” (Zizioulas 2001, 109). He bases such catholicity on the Eucharist: “Catholicity . . . does not mean anything else but the wholeness and fullness and totality of the body of Christ ‘exactly as’ . . . it is portrayed in the eucharistic community” (Zizioulas 2002, 149). Thus, he insists: “Orthodox ecclesiology is based on the idea that wherever there is the Eucharist there is the Church in its fullness as the Body of Christ” (Zizioulas 1994, 421; see also DeClue, “Eucharistic Ecclesiologies,” 81).

As Tillard phrases it, “wherever there is true Eucharist there is truly Church”; “Church is, therefore, every local community gathered together by the Eucharist” (Tillard 1992, 28). According to him, “the church where each bishop presides—is not simply a part of the Church of God. It is the Church of God in one of her manifestations in the here and now. . . . The eucharistic community is not a fragment of the mystery of the universal Church, but an appearance of this Church” (Tillard 1983, 150–151). 

Likewise, Kasper does not view the local church as a mere segment of the universal Church. “The local church is neither a province nor a department of the universal church; it is the church at a given place” (Kaspar 2000, 325). In a relatively early work, Ratzinger similarly writes that “the individual local Churches . . . are not separate parts of a larger administrative organization but rather embody the totality of the reality which is ‘the Church’” (Ratzinger 1965, 44). Tillard offers a comparable comment. Speaking of the local churches, he writes that “each of them is . . . the Church of God: One, Holy, Catholic, and Apostolic. . . . Each is the Church by being the authentic presence of the ephapax [once for all] of the apostolic Church in one of the places and times where humanity lives its destiny” (Tillard 1995, 553; translation my own). As the CDF phrases it, “although they are particular, the universal Church becomes present in them with all its essential elements” (Communionis notio, no. 7). 

The fact that each particular church is fully church, qualitatively speaking, does not mean that the particular churches are entirely independent. Such a view has been attributed to Afanasiev, who wrote: “in the apostolic age, and throughout the second and third centuries, every local church was autonomous and independent—autonomous, for it contained in itself everything necessary to its life; and independent, because it did not depend on any other local church or any bishop whatever outside itself” (Afanasiev 1992, 107). However, this view is not shared by the majority of eucharistic ecclesiologists.

The CDF describes such an erroneous opinion as follows: “It is claimed that, where the Eucharist is celebrated, the totality of the mystery of the Church would be made present in such a way as to render any other principle of unity or universality non-essential” (Communionis notio, no. 11). The CDF goes on to argue exactly the opposite, appealing to the Eucharist as the basis for its position:

These and similar errors do not take sufficiently into account that it is precisely the Eucharist that renders all self-sufficiency on the part of the particular Churches impossible. Indeed, the unicity and indivisibility of the eucharistic Body of the Lord implies the unicity of his mystical Body, which is the one and indivisible Church. From the eucharistic centre arises the necessary openness of every celebrating community, of every particular Church; by allowing itself to be drawn into the open arms of the Lord, it achieves insertion into his one and undivided Body. (Communionis notio, no. 11)

An authentic eucharistic ecclesiology, then, must not only affirm the full ecclesial quality of the particular church but must also find a way to account for the unity of local churches and the reality of the one, universal Church. Eucharistic ecclesiologists approach this question in different ways, using various conceptual formulations to express their understanding.

Tillard makes a distinction between the full ecclesial quality of the local church (qualitative catholicity) on the one hand and the entirety of the Church (quantitative catholicity), on the other. “The local Church . . . has the wholeness of the Church but it is not the whole Church” (Tillard 1995, 77; translation my own). As the title of one of his books suggests, Tillard understands the one Church as a Church of churches or communion of communions: “a communion of local Churches, spread throughout the world, each one itself being a communion of the baptized, gathered together into communities by the Holy Spirit, on the basis of their baptism, for the Eucharistic celebration” (Tillard 1992, 29).

Kasper, for his part, holds that the local and universal Church are “in and from” one another. Citing points of agreement with Ratzinger, based on shared acceptance of Catholic doctrine, Kasper writes:

The one church of Jesus Christ exists “in and from” the local churches [see Lumen gentium,/em>, no. 23]. It exists, therefore, in each local church; it is present there especially in the celebration of the Eucharist. It follows that there can be no local church in isolation, for its own sake, but only in communion with all other local churches. . . . As the universal church consists ‘in and from’ local churches, so each local church exists “in and from” the one church of Jesus Christ [see CDF, Communionis notio, no. 9]. The unity of the universal church is a unity in communion. . . . The local churches and the universal church mutually include each other. (Kasper 2000, 329)  

Zizioulas employs the phrase “unity in identity” to express the locality and universality of the Church. He is worth quoting at length on this point:

Identified as she is with the One whole Christ, each [particular] “Catholic Church,” in communion with the other Churches like her, is not a part of a whole; ,em>but nor can it be said that she can live cut off from the others. For her wholeness and fullness are not her exclusive and private possession. It is the one Christ who Himself, however, lives and is incarnate identically in the other Churches too. In order for each Church to be the body of Christ, then, she cannot but be identified with the other Churches constituting with them one sole Church in the whole world. This is precisely what is implied by the thesis of this work according to which the unity of the Church throughout the world is a unity in identity. It is the identity of the Churches with the one Christ and with each other which means that no local Church can be a “Catholic Church” if she is cut off from the rest. (Zizioulas 2001, 260, emphasis original)

Perhaps the point being made by Zizioulas can be exemplified through a direct comparison between local churches and communion hosts. Even though “this” host is not “that” host, each host is wholly Christ; Christ is fully present in every host. Even though “this” local church is not “that” local church, each local church is fully Church; the one Church is present with all her fullness in each particular church. In some sense, there is a unity in identity, because each church is the embodiment of the same reality in a manner analogous to the fact that every host is the same Jesus Christ in his fullness. 

Ratzinger offers some similar remarks: “Christ is wholly present everywhere, that is the one very important thing the Council formulated in common with our Orthodox brethren. But he is only one everywhere, and therefore I can have the one Lord only in the unity that he himself is, in the unity with the others who also are his body and are to become it ever anew in the Eucharist” (Ratzinger 1986, 244). More starkly, he writes elsewhere: “The Eucharist is celebrated with the one Christ, and thus with the whole Church, or it is not being celebrated at all” (Ratzinger 2005, 106).

On the question of the ontology of the universal Church, however, Zizioulas shows some marked disagreement with the Catholic theologians discussed here, especially in comparison to Ratzinger. Zizioulas claims:

In a eucharistic view of the Church this means that the local Church . . . is the only form of ecclesial existence which can be properly called Church. All structures aiming at facilitating the universality of the Church create a network of communion of Churches, not a new form of Church. . . . Any structural universalization of the Church to the point of creating an ecclesial entity called “universal Church” as something parallel to or above that of the local Church would inevitably introduce into the concept of the Church cultural and other dimensions which are foreign to a particular local context. (Zizioulas 2002, 258, emphasis original)

Contrary to Zizioulas’s view, Ratzinger (and the CDF under his prefecture) emphasizes the precedence of the universal Church. Ratzinger holds that “what first exists is the one Church, the Church that speaks in all tongues—the ecclesia universalis; she then generates Church in the most diverse locales, which nonetheless are all always embodiments of the one and only Church. The temporal and ontological priority lies with the universal Church” (Ratzinger 1966, 44).

To Ratzinger, this position is a clear fact, so much so that he finds it difficult to entertain competing explications. “The ontological precedence of the Church as a whole, of the one Church and the one body, of the one bride, over the empirical and concrete realizations in the various individual parts of the Church seems to me so obvious that I find it difficult to understand the objections raised against it” (Ratzinger 2005, 135). From this perspective, he is more hesitant to speak about a communion of communions. Rather, “the one Church is a theological entity, and not the subsequent uniting of many churches” (Ratzinger 2005, 249). As the CDF teaches, “‘the universal Church cannot be conceived as the sum of the particular Churches, or as a federation of particular Churches.’ It is not the result of the communion of the Churches, but, in its essential mystery, it is a reality ontologically and temporally prior to every individual particular Church” (Communionis notio, no. 9).

Kasper agrees with this to a degree. He admits that “the universal church is not the mere sum of the local churches. . . . The church is not like the federation of several states” (Kasper 2000, 329). Nevertheless, he takes issue with the idea of the ontological and temporal priority of the universal Church (see Kasper, “On the Church,” 325 and 329; idem., “Zur Theologie,” 43). He does not want to give priority to either the local church or the universal Church. “The local churches and the universal church are intimately united. They share the same existence; they live within each other” (Kasper 2000, 329). Kilian McDonnell explicates Kasper’s position by stating that “the universal Church and local churches exist simultaneously. . . . When one speaks of the ‘one, holy, catholic, and apostolic Church’ one does not mean just the universal Church, as though the universal Church existed as an abstraction, apart from its realization in the local churches of the world. No. What is meant is the concrete Church which is at the same time local and universal” (McDonnell 2002, 712–713).

Kasper’s vision is somewhat akin to that of Tillard. While Ratzinger views Pentecost as the birth of the Church universal, “speaking all tongues,” Tillard points to Pentecost as the establishment of both a local church and the universal Church. Aidan Nichols, O.P. (b. 1948), explains Tillard’s view thus: “the Church founded in this Jerusalem ‘cell’ by the effusion of the Spirit is destined, actually, for all the world. And so Tillard can conclude that the Church (the universal Church) and the first local Church (the church of Jerusalem) come into existence simultaneously. For Tillard, this simultaneous origin of the universal Church and the local church is what explains how the Church can multiply without dividing, how there can be more and more ‘churches of God’ in different places without there being any less one single ‘Church of God’” (Nichols 2002, 117; see also DeClue, “The Eucharist”).

Other than viewing the Church born on Pentecost as both the local church of Jerusalem and the universal Church, Tillard’s views regarding the establishment of the other local churches are quite similar to Ratzinger’s. The fundamental notion is that Christ establishes the one Church, which then makes herself present in each place with all of her constitutive dimensions. The local churches, in this sense, receive their existence from the one Church.

For Ratzinger, this receptivity is crucial (see “The Ecclesiology of the Second Vatican Council,” 244) and applies to the Church’s eucharistic character. “The fact that the sacrament of priestly service is requisite for the Eucharist is founded upon the fact that the congregation cannot give itself the Eucharist; it has to receive it from the Lord by the mediation of the one Church” (Ratzinger 2005, 143). Particular churches are not self-sufficient or self-sustaining. Traditionally, for a new bishop to be consecrated for a vacant see, at least three other bishops (often from the surrounding local churches) would participate. In the Catholic and Orthodox Churches alike, a local church does not decide completely by itself who its new bishop will be, especially when a new diocese or eparchy is being established for the first time:

Since the local church does not give itself its bishop (that is, it cannot ordain him without other bishops from other churches), it cannot give itself the Eucharist; it must first receive the sacraments and church structure from without, before it can be established as a local (even catholic) church. In other words, from Ratzinger’s perspective, there are not first many local churches each springing up independently, which then establish communion with one another in recognition of their mutual identity as churches. There is first the one Church (quite real and concrete) established by Christ, which then goes forth into the world and makes herself present in various places in and through local churches, which are fully churches only because they have received from the one Church all the necessary ecclesial elements (including baptism, holy orders, and most especially the Eucharist). (DeClue 2014, 89; see DeClue, The Mind of Benedict XVI, 237–242)

The episcopal pre-conditions for the celebration of the Eucharist and, consequently, for the establishment of a local church lead to an essential consideration: the hierarchical constitution of the Church in relation to the Eucharist.

As already mentioned, all of the theologians under discussion here affirm that the local church, properly speaking, is the diocese or eparchy, not the parish. Furthermore, they all hold this view for the same reason: the bishop is the principal presider over the Eucharist within his territory. As St. Ignatius of Antioch teaches: “Let the celebration of the Eucharist be considered valid which is held under the bishop or anyone to whom he has committed it. Where the bishop appears, there let the people be, just as where Jesus Christ is, there is the Catholic Church. It is not permitted without authorization from the bishop either to baptize or to hold an agape” (Letter to the Smyrnaeans, no. 8).

Here, we encounter the connection between the Eucharist and the mark of apostolicity. As Zizioulas notes: “Apostolic succession as an historical fact stemmed from the Divine Eucharist, in the offering of which the Bishops succeeded the Apostles. This becomes clear from studying [the First Letter of St.] Clement where the meaning of succession from the Apostles revolves exclusively around the ministry of ‘offering the Gift’” (Eucharist, Bishop, Church, 65–66). Ratzinger concurs, as Maximilian Heinrich Heim (b. 1961) explains: “Ratzinger sees apostolic succession as the guarantee for the legitimacy of the Eucharist, which is necessary for the fulfillment of its life-giving purpose” (Heim 2007, 282). Thus, Ratzinger writes: “A Church understood eucharistically is a Church constituted episcopally” (Ratzinger 1966, 79).

It is for this reason that the name of the local ordinary is proclaimed in the Eucharistic Prayer. Likewise, Vatican II “teaches that by Episcopal consecration the fullness of the sacrament of Orders is conferred, that fullness of power, namely, which both in the Church’s liturgical practice and in the language of the Fathers of the Church is called the high priesthood, the supreme power of the sacred ministry” (Lumen gentium, no. 21).

This understanding of the particular church is reflected in the Code of Canon Law (CIC). It states: “Particular churches, in which and from which the one and only Catholic Church exists, are first of all dioceses” (can. 368). It then goes on to define “diocese” in connection with the bishop and the Eucharist: “A diocese is a portion of the people of God which is entrusted to a bishop for him to shepherd with the cooperation of the presbyterium, so that, adhering to its pastor and gathered by him in the Holy Spirit through the gospel and the Eucharist, it constitutes a particular church in which the one, holy, catholic, and apostolic Church of Christ is truly present and operative” (can. 369; cf. Code of Canons of the Eastern Churches, can. 177).

Zizioulas offers a helpful explication of why this is the case, especially from a eucharistic perspective. “The identification of the eucharistic assembly with the ‘Church of God’ led naturally to the coincidence of the structure of the Church with that of the Eucharist” (Zizioulas 2001, 59). Historically, Zizioulas contends that the standard practice in the very early Church was for there to be one celebration of the Eucharist under the presidency of the bishop, surrounded by his presbyters and deacons with the people. The parish system did not begin until the middle of the third century and was not solidified until sometime in the fourth century, for pragmatic reasons. As the church grew, the bishop could not be present physically at each divine liturgy (Zizioulas 2001, 218–227). Nevertheless, “the eucharistic synaxis that takes place without him is in essence nothing other than the Eucharist which is under his leadership, which he had joined in convoking and at which he was spiritually present” (Zizioulas 2001, 220).

Tillard, too, describes the situation surrounding the parish system in connection with the bishop and the Eucharist. He writes: “The local Church becomes the totality of these Eucharistic communities in communion with this bishop, and also within the area of his See. The Church is itself, therefore, a communion of local communities. In today’s terminology it is a diocese (entrusted to a bishop), made up of parishes, each one of these being a Eucharistic community” (Tillard 1992, 29). The office of bishop thus serves the unity of the eucharistic celebrations within the local church.

While the bishop is a point of ecclesial unity within his diocese, that is not the bishop’s only role. As mentioned earlier, eucharistic ecclesiologists—with few exceptions—recognize the need for the particular churches to be in communion with one another. This need is fulfilled through episcopal collegiality and synodality, the latter of which Tillard understands to be the communion of the local churches with one another through the collegial unity of their bishops (see Tillard 1991, 115).

Even Zizioulas, whom we have seen emphasize the local church, acknowledges the supra-diocesan aspect of episcopal ministry. “The bishop is both a local and a universal ministry. The bishop is ordained for a particular Church in order to be its head and center,” but, Zizioulas continues, “he is at the same time a bishop of the church universal” (Zizioulas 1999).

Part of the bishop’s role is to keep his local church within the universal communion of the one Church. As Heim explains, “an essential part of the eucharistic structure of the local community is the horizontal relation of its bishop to the college of bishops” (Heim 2007, 278). If apostolic succession serves the diachronic unity (throughout time) of the Church and of the churches, collegiality serves synchronic unity (across the globe at the same time).

Relatedly, Tillard writes that in the bishop “are personified the particular place and distinct function this [particular] Church has within the communion of Churches. . . . representing it in the communion of Churches (synodality) and of bishops (collegiality), causing it to play its part in councils and making its particular tradition ever-present and active in the ecclesial symphony. On the other hand, he is responsible for preserving the faith of his plebs and has the mission of nurturing it by keeping it within the communion of all the Churches, above all, through the Eucharist” (Tillard 1991, 115). As he states elsewhere: “The bishop is only bishop of his church in the communion (synodality) of catholic Churches” (Tillard 1995, 251; translation my own).

Of course, according to Catholic teaching, the unity of the episcopal college is effectuated through unity with the See of Rome and its bishop, the pope. Interestingly, while he understands the nature and authority of universal primacy in a different way, Zizioulas also affirms its necessity. On this point, he rejects common Orthodox reductions of primacy to the level of ecclesial right in contrast with the divine right of synods. “The main weakness of this position lies in that it seems to overlook the simple and obvious fact that synodality cannot exist without primacy. There has never been and there can never be a synod or a council without a protos. If, therefore, synodality exists jure divino . . . primacy also must exist by the same right” (Zizioulas 2006, 237). In fact, Zizioulas goes so far as to say that “Primacy is also a ‘sine qua non conditio’ for the catholicity of the Church” (Zizioulas 1999, 121).

The CDF similarly teaches that universal primacy is required to safeguard the full catholicity (i.e., the full ecclesial quality) of the local churches:

But for each particular Church to be fully Church, that is, the particular presence of the universal Church with all its essential elements, and hence constituted after the model of the universal Church, there must be present in it, as a proper element, the supreme authority of the Church: the Episcopal College ‘together with their head, the Supreme Pontiff, and never apart from him.’ The Primacy of the Bishop of Rome and the episcopal College are proper elements of the universal Church that are ‘not derived from the particularity of the Churches,’ but are nevertheless interior to each particular Church. Consequently, ‘we must see the ministry of the Successor of Peter, not only as a ‘global’ service, reaching each particular Church from ‘outside,’ as it were, but as belonging already to the essence of each particular Church from ‘within.’” . . . The ministry of the Successor of Peter as something interior to each particular Church is a necessary expression of that fundamental mutual interiority between universal Church and particular Church. (Communionis notio, no. 13, emphasis original)

Communion with the Roman Pontiff, then, is not extrinsic to the particular church but is an aspect of its full catholicity. As the CDF says earlier in the same document: “the unicity and indivisibility of the eucharistic Body of the Lord implies the unicity of his mystical Body, which is the one and indivisible Church. . . . For this reason too, the existence of the Petrine ministry, which is a foundation of the unity of the Episcopate and of the universal Church, bears a profound correspondence to the eucharistic character of the Church” (Communionis notio, no. 11).

McPartlan explains this passage well:

The pope, in short, is here being understood as eucharistic guardian and guarantor, as one who primarily strengthens his brother bishops not juridically but eucharistically. He supports the eucharistic presidency of each local bishop, with whom he is named in the eucharistic prayer, and exercises a ministry of vigilance . . . to ensure that the eucharistic lives of the many local churches are in harmony with one another in their witness to the world of today and in harmony, also, with the witness of past ages, because the fact that all are striving to live out the same mystery in their own locality, means that the witness of each affects all, for good or ill. (McPartlan 1995, 70)

McPartlan also attributes such a view to Ratzinger. “Long before he became Prefect for the Congregation, Joseph Ratzinger already held, as Battista Mondin neatly summarizes, that ‘the primacy of the pope does not primarily concern either orthodoxy or orthopraxy, but rather ortho-Eucharist” (McPartlan 1995, 70n7, quoting Mondin, Le nuove, 171). Tillard, too, has a profound way of expressing this point: “The purpose of the papacy is to give the Eucharist its full dimensions” (Tillard 1983, 189; see DeClue, “The Eucharist”).

How so? As we saw above, Aquinas held that the ultimate grace-reality of the Eucharist—its res tantum—is the unity and communion of the mystical body of Christ. Every offering of the Eucharist, then, ought to be celebrated in communion with the one Church throughout time and across the world. Quantitative catholicity (universality) is a necessary component of and condition for qualitative catholicity (full ecclesial quality). The Roman Pontiff supports the role of each bishop within his own diocese and simultaneously enables the eucharistic celebrations in the various local churches to be in communion with the whole Church. In short: collegiality is necessary in order for the Eucharist to be celebrated properly in each local Church. Collegiality requires primacy. Therefore, primacy serves the proper celebration of the Eucharist, even on the local level. In order for the unity that the Eucharist effects to be realized, the particular celebrations must be unified. The papacy provides the visible and structural means by which this unity is maintained and manifest, which is essential for the very catholicity of the particular churches themselves.

These considerations regarding the Eucharist and primacy lead to the topic of the Church’s telos or mission. As Tillard relates: “God’s design is to sum up all things in Christ ([Eph] 1:10), to make all Jews and Gentiles into one new humanity (2:15) by breaking down the dividing wall (2:14) and its barriers. As with everything in the Church of God, primacy is essentially related to the nature of this divine purpose” (Tillard 1998, 198).

IV. The Mission of the Church

The Church’s mission was given by Christ himself: “Go therefore and make disciples of all nations” (Mt 28:19). After the descent of the Holy Spirit at Pentecost, the apostles went out to begin fulfilling this command. After Peter’s bold proclamation of repentance and the call for baptism, “there were added that day about three thousand souls. And they held steadfastly to the apostles’ teaching and fellowship [communion], to the breaking of the bread [the Eucharist] and to the prayers” (Acts 2:41b–42).

Herein, the telos of the Church is revealed. The ultimate goal is the salvation of humankind. The proximate goal leading to salvation is incorporation into the communion of the Church. As Gaudium et spes teaches, “the Church has a single intention: that God’s kingdom may come, and that the salvation of the whole human race may come to pass. For every benefit which the People of God during its earthly pilgrimage can offer to the human family stems from the fact that the Church is ‘the universal sacrament of salvation’” (no. 45; see also Ad gentes, no. 1).

The communion of the Church is salvific; it is the result of Christ’s saving work and is effectuated most aptly through the Eucharist. As Lumen gentium teaches: “Christ . . . sent His life-giving Spirit upon His disciples and through Him has established His Body which is the Church as the universal sacrament of salvation. . . . He is continually active in the world that He might lead men to the Church and through it join them to Himself and that He might make them partakers of His glorious life by nourishing them with His own Body and Blood” (no. 48).

Hence, one of the chief ways that the Church leads to the sanctification of humankind is through the Eucharist, which—as has already been shown—effects the communion of the members of the Church. As Christ says in John 6:54, “he who eats my flesh and drinks my blood has eternal life, and I will raise him up at the last day.” Joining this passage with the references from Vatican II, McPartlan explains why he chose the title Sacrament of Salvation for his book on eucharistic ecclesiology: the term applies to both the Church and to the Eucharist (McPartlan 2008, xv).

Salvation involves reestablishing communion between God and humanity, which in turn leads to the unity of humans with one another. The Church as the sacrament of this unity is the sacrament of salvation. Incorporation into the Church, then, is not entirely distinct from salvation but is, rather, the beginning of that salvation, which will reach its complete fulfillment in the Eschaton. The Church not only has salvation as its goal; in its eschatological existence, it is that goal. As Aquinas teaches: “To be a glorious Church not having spot or wrinkle is the ultimate end to which we are brought by the Passion of Christ” (ST III, q. 8, a. 3, ad 2).

If salvation is a sharing in divine life, and divine life is communal, then salvation is also communal. As Nichols expresses it: “If heaven depends on being with Christ, then it must entail a co-being with all those who are members of his body” (Nichols 2005, 186). As Ratzinger elaborates: “Heaven is a stranger to isolation. It is the open society of the communion of saints, and in this way the fulfillment of all human communion. This is not by way of competition with the perfect disclosure of God’s Face, but, on the contrary, is its very consequence” (Ratzinger 1988, 235). Later, he adds: “For the redeemed are not simply adjacent to each other in heaven. Rather, in their being together as the one Christ, they are heaven” (Ratzinger 1988, 238).

The communion of saints in heaven has its foretaste and beginning in the communion of the Church on earth. Hence, the title of Chapter VII of Lumen gentium is “The Eschatological Nature of the Pilgrim Church and Its Union with the Church in Heaven.” On this point, we encounter the confluence between the Church’s final cause, her communal formal cause, and her eucharistic dimension. It is primarily in the Eucharist that the Church is most fully connected with her eschatological goal: participating in the heavenly liturgy. As Tracey Rowland notes, Vatican II “emphasized that the earthly liturgy is an anticipation of the heavenly one, so that at the same time as it renews the Paschal mystery it anticipates the consummation of the work of redemption and the renewal of the cosmos at the end of time” (Rowland 2008, 123–124). As Pope Benedict XVI teaches: the eucharistic liturgy is “a real foretaste of the eschatological fulfillment for which every human being and all creation are destined” (Sacramentum caritatis, no. 30). Continuing, he writes: “Consequently, every eucharistic celebration sacramentally accomplishes the eschatological gathering of the People of God. For us, the eucharistic banquet is a real foretaste of the final banquet foretold by the prophets (cf. Is 25:6–9) and described in the New Testament as ‘the marriage-feast of the Lamb’ (Rev 19:7–9), to be celebrated in the joy of the communion of saints” (Sacramentum caritatis, no. 31; see also Presbyterorum ordinis, no. 5).

Catholics and Orthodox hold this view in common: “the church celebrates the eucharist as expression here and now of the heavenly liturgy” (Joint International Commission 1982, no. 4c). As the Catechism teaches: “To the offering of Christ [in the Eucharist] are united not only the members still here on earth, but also those already in the glory of heaven. In communion with and commemorating the Blessed Virgin Mary and all the saints, the Church offers the Eucharistic sacrifice” (no. 1370).

The Eucharist, therefore, pertains not only to the communion of the Church on earth but also to her heavenly state. Indeed, both dimensions meet in the sacred liturgy. As Roland Millare phrases it: “Communion with the Logos in the celebration of the liturgy enables a person to be contemporaneous with the eternal liturgy, in which every member of the communion of the Church and the communion of saints participates” (Millare 2022, 207).

Zizioulas connects the eschatological character of the Church to the Church’s essence: “[The Church] is the great mysterium fidei, precisely by being in this world but not of this world, by drawing, that is, her identity from what she will be. All this makes the Church an eikon of the Kingdom to come” (Zizioulas 1988, 300). He further connects this to the Eucharist: “What each eucharistic community . . . was meant to reveal, was not part of Christ but the whole Christ and not a partial or local unity but the full eschatological unity of all in Christ” (Zizioulas 2002, 154).

De Lubac concurs with this explication. As McPartlan relates: “Through the veil of the eucharistic elements, Christ in glory reaches to the Church on earth in order to draw her back through the veil and embody her in the Church of heaven. Thus, when de Lubac says that the Eucharist makes the Church, it is the heavenly Church within the eucharistic veil that he intends” (McPartlan 2006, 85).

The Church draws her life from the Eucharist not only by making the past present but also by participating in the future. McPartlan finds warrant for this vision in Hebrews 12:18, 22–24. He writes, speaking of the Eucharist: “Though it appears to be only a modest gathering to which they have come, the writer [of Hebrews] urges the local Christians to see with eyes of faith what they have really come to, namely the final gathering of all the ages on God’s holy mountain” (McPartlan 1995, 4). “[W]hat breaks upon this world wherever the Eucharist is celebrated is the assembly of all the angels and saints surrounding Christ in his glory in the heavenly Jerusalem, nothing less than the assembly of the last day” (McPartlan 1995, 4–5). Hence, it is precisely in the Eucharist—a participation in the eschaton—that the Church on earth fulfills her mission most fully.

Relatedly, Pope St. John Paul II sees the Church’s earthly life as a continual circular movement, proceeding forth from the Eucharist to bring the salvation of Christ to the world and then bringing the converted back to the Eucharist. “From the perpetuation of the sacrifice of the Cross and her communion with the body and blood of Christ in the Eucharist, the Church draws the spiritual power needed to carry out her mission. The Eucharist thus appears as both the source and the summit of all evangelization, since its goal is the communion of mankind with Christ and in him with the Father and the Holy Spirit” (Ecclesia de Eucharistia, no. 22). The Eucharist, then, is profoundly linked to the Church’s final cause, her ultimate goal: the extension of communion with the Trinity through Christ which she herself is and will be eternally.

V. Conclusion

This article has shown that the Eucharist pertains to the Church in her origin, nature, structure, and mission. The institution of the Eucharist and the beginning of the Church are intrinsically tied together. It is the Eucharist that effects the Church as a communion of the members of the body of Christ. This communion constitutes the essence of the Church’s nature. The structure of the Church enables and exemplifies this communion throughout time and across the world through apostolic succession and episcopal collegiality, the latter being unified through the universal primacy of the Roman pontiff. This hierarchical constitution is directly tied to the celebration of the Eucharist, which calls for communion on the local and universal levels alike. Without such unitive structure, the celebration of the Eucharist would be imperfect, failing to manifest the unity it was established to bring about. It is through the Eucharist that the Church receives the spiritual strength to carry out the mission of adding all of humanity to herself with the ultimate goal of leading all to salvation as members of the communion of saints, whose own heavenly liturgy is anticipated and participated in through the eucharistic synaxis.

Eucharistic ecclesiology thus profoundly expresses a nexus of several mysteries of the faith. It also serves as the most promising starting point for ecumenical dialogue between the Catholic and Orthodox Churches, due to a shared understanding of the intrinsic relationship between the Church and the Eucharist. This shared vision provides a framework for addressing the issues which still divide. While the division with Protestants is greater than between the Catholic and Orthodox Churches, even in ecumenical dialogue with and between Protestants, the importance of the Eucharist for ecclesial communion is gaining greater recognition.

It is not without justification, then, that the Second Vatican Council, in its Decree on Ecumenism, Unitatis redintegratio, points to common celebration of the Eucharist in a reunited Church as the final step and ultimate goal of all ecumenical activity. For, “when the obstacles to perfect ecclesiastical communion have been gradually overcome, all Christians will at last, in a common celebration of the Eucharist, be gathered into the one and only Church in that unity which Christ bestowed on His Church from the beginning” (no. 4).