"Since we now live the story Scripture tells, Scripture does not merely inform us about the course of this story, for persons live historically by discourse, by address and respones to one another. Thus Scripture is not merely a record of divine-human history but a proclaiming of it, not merely an account of God's life with us to date but a voice in that life. When we read Scripture in the church, someone addresses us. And by the unanimous tradition of the church, this voice is the Word of God, the Logos, the second identity of the Trinity.
"Moreover, by the teaching of those who have reflected most profoundly on this mystery -- Irenaeus, Athanasius, Cyril, Maximus, Luther, Edwards, Barth -- the Logos who speaks is not merely some posited metaphysical extra entity but the actual Logos, that is, the incarnate Word, the Word that God speaks as Jesus the crucified and risen Christ. Pastors sometimes introduce the reading of Scripture by saying, 'Listen for the word of God.' When Irenaeus of Athanasius listened for the Word of God in their Scripture, it was their Lord Christ they listened to hear, whether the text at hand came from Matthew or Isaiah or Moses or David. The religiously vital preexistence of Christ was, for them, precisely his preexistence in the Old Testament as the voice that speaks there, just as the New Testament was the voice of his continuing prophetic activity.
"But is it not absurd to think of the Word as in any sense incarnate before the flesh existed, before Jesus was born? So that it could be the incarnate Word who spoke to Moses on the mountain or who cried out to his Father in many psalms? Or is it not absurd to think of the writing and collecting and reading and interpreting of the New Testament as this same Word's actual speech to us, who, as the angel said, is not here but risen?
"The claim that the incarnate Christ speaks in all Scripture sounds preposterous, I suggest, only because we unthinkingly make an (in itself rather naive) assumption about time: that it glumly marches on, that someone born in 4 B.C. could not have spoken to and through Jeremiah or that someone who died in A.D. 30 could not have spoken through, say, the seer John. But time, in any construal adequate to the gospel, does not in fact march in this wooden fashion. Time, as we see it framing biblical narrative, is neither linear nor cyclical but perhaps more like a helix, and what it spirals around is the risen Christ. Thus John, having said in his prologue that the Word 'became' flesh, presumably when Jesus was born, presents us with this enfleshed Word, in a context that makes his human enfleshment as obtrusive and, indeed, offensive as possible, and has him say, 'Before Abraham was, I am.' Which, then comes first, the incarnation or Abraham? It depends entirely on which chapter of John you are in; that is, it depends on the discoursive context.
"So Luther's dictum that in the Psalms we find the prayer of Christ and all the saints is not the imposition on these texts of an alien 'Christian' interpretation. If the gospel is true, it is simply the fact of the matter. Or -- to stay with Luther -- his exhortation to take Aaron as Christ, the great high priest (and so on for all the characters of the exodus story), and thus to read sections of the Pentateuch as something like another Gospel is simply a pointer to Exodus's plain sense.
"The unity of Scripture is much tighter than we in modernity have dared to think. If the Word of the Lord that came to Second Isaiah and made him a prophet was Jesus Christ, then the vision of Christ that the church has derived from this prophet, of a 'man of sorrows and acquainted with grief,' is not a mere allowable trope but is in fact a product of Christ's own testimony to his own character, given by the mouth of his prophet. If the Word of the Lord, to whomever it comes, is Jesus, then we can indeed find out about the historical Jesus Christ from Isaiah or Zechariah or David, and about what Isaiah or Zechariah really meant from Jesus' teaching and story.
"At the end of this stretch of my argument, [a] hermeneutical word. Do not be intimidated by the dogma that properly 'historical' exegesis will not find Jesus in the Old Testament or discover Paul's intent by reading, say, Leviticus. This dogma is a mere metaphysical prejudice, which, as such, may of course be right -- but then again may not be. Properly biblical reading of the Bible must, I suggest, proceed on the assumption that it is a false prejudice."
--Robert W. Jenson, "Scripture's Authority in the Church," in The Art of Reading Scripture (ed. Ellen F. Davis and Richard B. Hays; Grand Rapids: Eerdmans, 2003), 34-36