In an essay on ‘The Eternal Signiﬁcance of the Humanity of Jesus for our Relationship with God’, Karl Rahner put it this way: ‘the Word—by the fact that he is man and insofar as he is this—is the necessary and permanent mediator of all salvation, not merely at some time in the past but now and for all eternity.’39
39 K. Rahner, Theological Investigations, trans. K. H. Kruger and B. Kruger, iii (London: Darton, Longman & Todd, 1967), 35 46, at 45; italics ours.
Augustine was second to none when it came to this eternal priestly mediation of Christ and to applying the image of head and body to the ﬁnal presence of all in Christ. He summoned Christians to their future life: ‘Be united in him [Christ] alone, be one reality alone, be one person alone (in uno estote, unum estote, unus estote)’ (In Ioannis Evangelium, 12. 9). From incorporation in Christ, Augustine moved to picture a profound solidarity with him, and even to a personal assimilation. Augustine, while expounding the resurrection of individuals to eternal life,40 also insisted that they will be drawn in the closest imaginable way into the reality of Christ: ‘and there will be one Christ loving himself (et erit unus Christus amans seipsum)’ (In Epistolam Iohannis, 10. 3).
40 See G. O’Collins, ‘Augustine On the Resurrection’, in F. LeMoine and C. Kleinhenz (eds.), Saint Augustine the Bishop: A Book of Essays (New York: Garland, 1994), 65 75.
Augustine also expressed the ﬁnal communion of life through Christ’s priestly mediation in terms of praise: ‘there we shall praise; we shall all be one, in him [Christ] who is One, oriented towards the One [the Father]; for then, though many, we shall not be scattered (ibi laudabimus, omnes unus in uno ad unum erimus; quia deinceps multi dispersi non erimus)’ (Enarrationes in Psalmos, 147. 28). Addressing the triune God, Augustine also wrote: ‘and without ceasing we shall say one thing, praising You [the Trinity] in unison, even ourselves being also made one in You [the Trinity] (et sine ﬁne dicemus unum laudantes te in unum, et in te facti etiam nos unum)’ (De Trinitate, 15. 28. 51).