“There is one body and one Spirit, just as you were called to the one hope of your calling, one Lord, one faith, one baptism, one God and Father of all, who is above all and through all and in all.” (Eph. 4:4-6)
Perhaps the reason why Paul is concerned that the Ephesians “make every effort to maintain the unity of the Spirit in the bond of peace” (Eph. 4:3) is that this unity, the unity of the individual congregation, is the proper reflection of the unity which is so ubiquitous in the “things of the Gospel,” so to speak. In other words, because there is one body and Spirit, one Lord, one faith, one baptism, one God and Father of all, Christians must also be united with one another in the Church. Plurality, division, strife, factions, disunity, fragmentation and the rest all serve as ways of defacing the proper image of the Church. Seeking unity is for Paul a way of living a life worthy of calling we have received (Eph. 4:1).
Disunity can arise in many different ways. For example, it might arise because of personal ambitions and conflicts among Christians. It might also arise because Christians do not or seemingly cannot agree amongst themselves on issues which they take to be very important, whether doctrinal or practical or both. It would be naïve to think that Christians ever existed in a pristine state of perfect unity at any point in the history of the Church, except perhaps at the earliest beginning (e.g., Pentecost). The Acts of the Apostles catalogues many examples of early Christian disunity, for example with respect to the inclusion of the Gentiles in the Church. Paul’s epistles likewise contain ample evidence that individual Christian congregations were afflicted by problems of conflict and disunity even in the first generation of Christians.
Paul teaches that there is one body and one Spirit. When he says “body” I presume he means to refer to the Church as the body of Christ, a metaphor which he has already used in this epistle (Eph. 1:22-23). One important question for Christian theology, especially in the present day, is: How is this body identified? How does it subsist? In what does it consist?
On this matter there are different opinions. Some in the Eastern Orthodox Church, for example, insist that one identifying marker of the body of Christ is the Eucharistic communion: where the Eucharist is, there is the Church, and where there exists communio in sacris, fellowship in holy things (viz., the Eucharist), there exists the Church. The Roman Catholic Church insists that the Church subsists in its fullness only in those congregations which are in full communion with the bishop of Rome. Protestants have their own opinions about this matter as well.
I am still thinking through these things myself, and this is a topic to which I will have to return in the future. For the time being, these are my thoughts.
If, as Paul says, the Church is the body of Christ, then the being of the Church consists in its connection to Christ. What is the most essential aspect of this connection to Christ? In my opinion, it is faith in Christ. This means that every person who has faith in Christ is a member of Christ’s body and thus a part of the Church. Paul also says elsewhere that “Anyone who does not have the Spirit of Christ does not belong to him” (Rom. 8:9). This must mean that there is a connection between faith in Christ and the possession of the Spirit; and indeed, it is precisely through the Spirit that faith is born in us. So the possession of faith in Christ and the possession of the Spirit, which go hand in hand, are necessary and sufficient conditions for belonging to the body of Christ, i.e. for being part of the Church.
What is faith? I have written about this in a paper titled “Claritas scripturae, theological epistemology, and the phenomenology of Christian faith,” which will be published in next year’s issue of Journal of Analytic Theology. In brief, I argue that faith is a kind of abiding preoccupation with Jesus Christ. I intentionally do not import too much dogmatic content into this definition, although of course I think that certain dogmas are more appropriate for the kind of abiding preoccupation I have in mind than are others. In my opinion, a person can have faith even though she might be wrong about very many things or even not have much of an opinion on diverse topics of Christian dogmatics. It is the person of Jesus which is central. Much more should be said about this, obviously.
Now things also get complicated when it comes to sacramental communion in the Church. For example, from the beginning Christians have also insisted on the necessity of the rite of baptism, a point which they learned from Christ Himself who told them: “Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, and teaching them to obey everything that I have commanded you” (Matt. 28:19-20). And yet there are instances in Scripture in which a person arguably demonstrates faith in Christ or possesses the Spirit apart from baptism: the thief on the cross is an example of the first, and the Gentiles who received the Spirit when Peter preached to them are an example of the second. There is reason for thinking that these are exceptional cases, of course, since the thief was nearing death and the Gentiles had to receive the Spirit before baptism in order for Peter and the other Jewish Christians to be positive that God had elected them while they were still Gentiles. To my mind, what is most reasonable to say is this: while faith in Christ and possession of the Spirit alone are jointly necessary and sufficient conditions for membership in the body of Christ, baptism in water is a very important rite which is “functionally necessary,” we might say, even though it is not absolutely, strictly necessary. In other words, if a person came to me and said that she wanted to be a Christian, I would insist that, among other things, she be baptized in water in the name of the Holy Trinity.
What basis might there be for establishing Eucharistic communion as a condition of membership in Christ’s body? Jesus says, “Very truly, I tell you, unless you eat the flesh of the Son of Man and drink his blood, you have no life in you. Those who eat my flesh and drink my blood have eternal life, and I will raise them up on the last day; for my flesh is true food and my blood is true drink. Those who eat my flesh and drink my blood abide in me, and I in them” (John 6:53-56). If we take this famous discourse to refer to the Eucharist, then it seems that there may be the beginning of an argument for Eucharistic fellowship as a condition for membership in Christ’s body. But this is to move too quickly. It is one thing for membership in Christ’s body to depend upon the fellowship with Christ’s body and blood which takes place in the Eucharistic meal, and it is another thing entirely for the Eucharistic communion to be mediated by means of an episcopal system. Communion with Christ in the bread and wine is one thing, it is “vertical,” and fellowship with a particular ecclesial system in which the Lord’s death is celebrated in the Eucharistic meal is another, it is “horizontal.” It must first be established the Eucharistic meal confers communion with Christ only when it is celebrated by the proper episcopal authorities.
For my part, I think that the fellowship with Christ which is conferred by the Eucharistic meal depends on Christ. Even in the episcopal system, it is not the bishop or the priest in his own power who makes the bread and wine to be the body and blood of Christ; the miracle takes place through the activity of the Holy Spirit. Fellowship with God always depends on the condescension of God. For this reason, it seems to me theologically justified to suppose that the Eucharistic meal, as it is celebrated in Protestant communities, can still confer eternal life and fellowship with Jesus, and this because Jesus makes it so, even apart from the mediation of the episcopal system.
If one accepts this view of things, then the Church as Christ’s body turns out to be a very diverse thing indeed. What all Christians have in common is faith, which I understand to be a kind of abiding preoccupation with the person of Jesus Christ, and this preoccupation arises within them as a result of the activity of the Holy Spirit. This preoccupation should lead them, in the ideal case, to gather together as a body and to celebrate the Lord’s Supper in remembrance of Him, as He commands us in Scripture, but at this point we have moved beyond a bare definition of the essence of Christian faith (and therefore membership in the body of Christ) and proceeded to a consideration of what healthy, “functional” faith looks like.