Consider the trinitarian ground of the “high priestly prayer” of Jesus for the unity of his church (John 17:11, 20-23). Jesus first makes a petition for unity in John 17:11:
I will remain in the world no longer, but they are still in the world, and I am coming to you. Holy Father, protect them by the power of your name—the name you gave me—so that they may be one as we are one.Jesus will expand on what this oneness means in vss. 20-23, but here we should note that this is a prayer for his disciples who will remain in the world after he has departed, a prayer that looks forward to the situation immediately following his ascension into heaven. Jesus says to his Father, “I am coming to you,” but the disciples will remain “in the world.” It is this state of affairs—their remaining behind without him in the world—that Jesus addresses in his prayer for their oneness. Somehow they will be “protected” or “guarded” if the Father answers Jesus prayer and grants them to “be one as we are one.”
That Jesus is speaking about the immediate future and the “survival” of his disciples’ after his own exit is confirmed by what comes after this petition for oneness (vss. 12-19). It is their remaining “in the world” that is Jesus primary concern. Even though he himself is leaving the world, he wants their joy to be complete in the world (v. 13). The world hates them (v. 14), but Jesus prays to his Father not that they be taken out of the world, but “that you protect them from the evil one” (v. 15). They are being “sent into the world” just as Jesus himself was, which is why they must be “sanctified by the truth” (vss. 17-18).
These contextual features argue against a purely “eschatological” reading of Jesus petition for oneness here in v. 11 or in the expanded prayer of vss. 20-23. Jesus is not merely praying for the perfect unity that will be fully established in the Church only at the eschaton. Rather, he is requesting immediate help for his disciples when he shortly leaves them behind. Their survival “in the world” will be dependent in some sense on their experiencing the kind of oneness that exists between Father and Son.
These petitions, therefore, are directly applicable to the issue of ecclesiastical life and unity in the present age. And Jesus expands the prayer to include “those who will believe in me through their message” in 17:20-23. Once again, as we discovered from the context of 17:11, there is nothing here to suggest that Jesus is now praying for a unity that will only be experienced at the Last Day. This eschatological reading ignores the connections between 17:11-19 and the 20-26. It is the same “world,” the one in which Jesus will leave his disciples when he departs, that is now in view when Jesus twice asks that the oneness of the new community (disciples and other belivers) result in the “world believing” that the Father has sent the Son (vss. 21, 23).
Having seen that Jesus prays for the unity of the left-behind community, we are faced with exegetical questions regarding the meaning of this oneness. First, it is a oneness which has as its archetype the unity of Father and Son (“that all of them may be one, Father, just as you are in me and I am in you,” v. 21a). "Just as" Father and Son are one, so the community of believers are to be one. But what does the phrase “just as you are in me and I am in you” refer to? What kind of unity does Jesus reference here?
I would suggest that Jesus is not referring to the ontological perichoresis (or circumincessio) that trinitarian theology traditionally uses to describe the shared essence or substance of divinity, or even the mutual interpenetration of the three divine persons. I am not denying the accuracy of such metaphysical assertions. I believe that the metaphysical and/or personal perichoresis of Father, Son, and Holy Spirit can be defended from other passages and maybe even at a secondary level from these passages.
It seems to me, however, that in this passage, where Jesus prays that these human creatures would exhibit the same kind of oneness as the Father and Son enjoy, he cannot have metaphysical or even ontological hypostatic perichoresis in view. Strictly speaking the divine perichoresis is a unique mode of divine existence. Neither is Jesus speaking of the ontological relationship between God and man, as Augustine seems to think (Augustine, Tractates on the Gospel of John 55-111, translated by John W. Rettig, in The Fathers of the Church, vol. 90 [Catholic University of America Press, 1994], p. 290). What is in view in Jesus’ prayer is something inter-personal, something that human creatures can emulate and image, not a metaphysical existence characteristic of the uncreated trinitarian mode of being. Moreover, the oneness that Jesus prays for is capable of maturation or completion (John 17:23), so it must admit of degrees. All of this suggests a oneness that is not fundamentally ontological.
Note: I am willing to grant what Volf claims—that the mutual giving and receiving of love spoken of in this passage and others “presupposes an already existing connection of some sort, however rudimentary” (Volf, After Our Likeness, p. 212). Such an ontological state of affairs may be presupposed in what Jesus prays for, but it does not help us explicate the meaning of the oneness for which he prays. Is there some sense in which God’s perichoretic mode of being as Father, Son, and Holy Spirit has been structurally reproduced within the created existence of humanity? Is the ontology of created human existence such that we inevitably exist in some deep structural sense in perichoretic relation to one another and all “partake” of one common human “nature”? Maybe. I’m not affirming or denying such a philosophical construct. Colin Gunton makes a good argument that the transcendental ground of human sociality resides in God’s trinitarian sociality (The One, the Three, and the Many: God, Creation and the Culture of Modernity, The Bampton Lectures, 1992 [Cambridge University Press, 1993], pp. 210-231). If, however, such a “trinitarian” anthropology is correct, it will have to be defended from other passages. I can find no evidence that John 17:11, 20-23 refers to, or assumes such a state of affairs. Jesus is praying for something that his left-behind community does not posses by virtue of their creation, but possibly something they have lost as post-lapsarian humanity. At any rate, he is praying that the Father grant to them something “extra,” that is the renewal of God’s intention in created human sociality.