2 Kings 19; Hebrews 1; Hosea 12; Psalms 135–136
THE CONTRASTS IN THE OPENING VERSES OF Hebrews 1 all tend in the same direction.
"In the past" contrasts with "in these last days." God spoke "to our forefathers" stands over against the fact that in these last days he has spoken "to us." In the past God spoke to the forefathers "through the prophets at many times and in various ways." But in these last days God has spoken to us "by his Son" (Heb. 1:1–2).
Indeed, the form of that expression, "by his Son," in the original, suggests pretty strongly that the author of Hebrews does not think of the Son as one more prophet, or even as the supreme prophet. The idea is not that while in the past the word of God was mediated by prophets, in these last days the word has been mediated by the Son, who thus becomes the last of the prophets. Something more fundamental is at issue. The Greek expression, over-translated, means "in Son." The absence of the article "the" is significant. Moreover, "in Son" contrasts not only with "through the prophets" but with "through the prophets at many times and in various ways."
The point is that in these last days God has disclosed himself in the Son revelation. In the past, when God used the prophets he sometimes gave them words directly (in oracles or visions), sometimes providentially led them through experiences they recorded, sometimes "spoke" through extraordinary events such as the burning bush: there were "many times" and "various ways" (Heb. 1:1). But now, God has spoken "in Son"—we might paraphrase, "in the Son revelation." It is not that Jesus simply mediates the revelation; he is the revelation. It is not that Jesus simply brings the word; he is himself, so to speak, the Word of God, the climactic Word. The idea is very similar to what one reads in the Prologue of John's Gospel. The Son is capable of this because he is "the radiance of God's glory and the exact representation of his being" (Heb. 1:3).
Strictly speaking, then, Christians are not to think of the New Testament books as just like the Old Testament books, bringing the next phase of God's redemptive plan to us. Mormons argue that that is all they are—and then say that Joseph Smith brought a still later revelation to us, since he was yet another accredited prophet. But the author of Hebrews sees that the climax of all the Old Testament revelation, mediated through prophets and stored in books, is not, strictly speaking, more books—but Christ Jesus himself. The New Testament books congregate around Jesus and bear witness to him who is the climax of revelation. Later books that cannot bear witness to this climactic revelation are automatically disqualified.