Why is it that, as claimed by John Calvin, T.F. Torrance, Karl Barth, and many others, Jesus Christ is the definitive revelation of God, the Word revealed to which the Word written attests in its whole and in all of its parts? Why is Jesus Christ the full unveiling of God such that we cannot, nor dare not, seek another God hidden somewhere behind his back, another dark mysterious deity whose final word of self-revelation has been hitherto concealed? H.R. Mackintosh explains from the gospel of John:
At various points the writer opens up, beyond this unity of Father and Son, a vista of its eternal character. He transcends the first three Gospels by insisting on the fact that the Sonship of Christ is increate and un-beginning, the presupposition of all time and history. In the beginning…He had been the Word with the Father. Ere coming from heaven He had lived a life somehow characterised by spiritual relationships (17:5); it was not some impersonal moment or tendency in God which had taken flesh and dwelt among men, but the Son, eternal object of the Father’s love (17:34), and possessed thereby of a perfect knowledge of the Father which was capable of reproducing itself in His earthly consciousness.
As one whose place is in the Father’s bosom (1:18) He presents God in propria persona. He knows God thus because He has always known Him so. “I speak the things which I have seen with My Father”; “no man hath ascended into heaven, but He that descended out of heaven.” Numerous other salient passages dwell on this prior life of Sonship. To the Jews’ question where He will go that they cannot come, He answers, “I am from above” (8:38). In the mysterious declaration, “Before Abraham was, I am” (8:58), the tense is apparently chosen to denote, as far as human speech permits, the timeless and unbecoming eternity of His inmost being. And in the upper room, He speaks to the Father of “the glory which I had with Thee before the world was”(17:5) and prays that it may be restored to Him.
Yet the main object of these statements is not to make certain speculative predications, in a so-called metaphysical interest, but to exhibit Jesus as the final revelation of the Father. This is the pivotal and organising idea in St. John’s theology. We can see the conviction in his mind that none can reveal perfectly save He who is that which He reveals. In His essential love, accordingly, the Father has poured forth His being in Jesus, that a perishing world may have life through Him. “Believest thou not,” Jesus asks, “that I am in the Father and the Father in Me? The words that I say unto you I speak not from Myself: but the Father abiding in Me doeth His works” (14:10). [H.R. Mackintosh, The Doctrine of the Person of Jesus Christ (New York: Charles Scribner’s Sons, 1912), pp.103-4.]
Quite simply, Mackintosh’s answer (which is nothing other than the apostle John’s answer!) is that Jesus is the final, ultimate, and definitive word of revelation because he is revelation himself. He does not come on God’s behalf to relay information about God; he is God himself, the Son in full equality and coinherence with the Father and Spirit, who makes God known within the confines and structures of our human capacities. Inasmuch as Christ is flesh, he is God accommodating himself to our understanding, as it were, with a lisp and a stammer (as Calvin put it); yet as God in flesh, he is eloquent and radiant (as Barth put it). Jesus is what he reveals, and therefore there can be no other revelation of God than what we see and hear and know in him, from now and throughout all eternity. In Jesus we have heard that eternal Word, and it is Love.