Writing in JETS 44:1 (March 2001), John Sailhamer says:
The Hebrew Bible is both text and commentary. If we ask what possible intertextual relationship lies between the compositional shape of the Pentateuch, the Prophets, and the Writings, I would suggest it is akin
to that of text and commentary. The Prophets and the Writings are not intent on giving us a new vision for the future. Their aim is to help us understand the messianic vision that has already been laid down in the Pentateuch and repeated in their own writings. God told the prophet Habakkuk, for example, to “write the vision” and also “to explain it” (Hab 2:3).
Like Habakkuk, the prophets wrote their vision along with its explanation. As Heschel put it, the interpretation of prophecy is already “an exegesis of an exegesis.” Our task is not to explain the prophetic vision, but to explain the prophets’ own explanation of their vision. The aim of the authors of the Prophets and the Writings was to provide a full and detailed textual commentary on the messianic vision that begins in the Pentateuch and is carried along through the rest of the Bible.
Like a stained glass window, the Prophets and the Writings give us the important bits and pieces of the prophets’ vision. I have in mind something like the way Isaiah 63 draws a glimmer of light from the poem in Gen 3:15 and passes it on to Daniel 7 through the prism of Genesis 49. From there on it passes through the NT on its way to the vision of the “rider on the white horse” in Revelation 19. Isaiah takes as his starting point the picture of the king who, in Genesis 49, “washes his clothes in the blood of grapes.” He then builds that picture into one of a mighty warrior treading in the wine presses of divine wrath. In doing so, Isaiah consciously links Genesis 49 to the first messianic poem in the Pentateuch, Gen 3:15. Isaiah has thus linked two strategically important poems in the Pentateuch (Genesis 3 and Genesis 49). In doing so, he shows that he is reading the Pentateuch along its compositional seams. As in a stained-glass window, the light he draws from the Pentateuch is given color and texture as it passes through the remainder of the OT. But also like a stained-glass window, these points of light converge into the larger picture.
Here, let me reiterate the point I made earlier. The line of thought reflected in Isaiah and Daniel and the book of Revelation is, I believe, the same as the historical intention of the Pentateuch itself. When Psalm 72 says of the Davidic king, “All the nations will be blessed in him,” it draws directly from the eschatology of the Pentateuch in Gen 12:3. When the same psalm says of the king’s enemies, “they shall lick the dust” (Ps 72:9b), it holds its vision up to a piece of light coming from Genesis 3.
In the same way, when speaking of the eschatological future, Hosea says, “Out of Egypt I have called my son.” In doing so, Hosea draws directly from the poetic vision of Balaam in the Pentateuch (Numbers 24). Also, by focusing on the poetic texts, Hosea shows he is reading the Pentateuch along its compositional seams. In the Numbers passage, Israel’s messianic future (in Numbers 24) is viewed in terms of their glorious past, that is, the exodus (in Numbers 23). The compositional strategy within the Pentateuch itself has thus linked the exodus with the messianic future. Hosea draws his own messianic hope from just those passages. Both Hosea and the Pentateuch see the fulfillment of their visions in terms of the same eschatological future, that is, “the last days” (בּHos 3:5; Num 24:14). Hosea’s messianic vision is thus cast as a commentary on the Pentateuch’s own messianic eschatology. Matthew’s application of the Hosea passage to Jesus suggests he has properly read both the Pentateuch and its commentary in Hosea.
Here we can take another example from the Emanuel prophecy in Isa 7:14. It is an all too common practice to look beyond the book of Isaiah and beyond the words of Isaiah 7 to the historically reconstructed social location of those words. When we do that, it becomes very difficult to see the kind of prophecy of a virgin birth that Matthew saw. But, if we look at the passage within the compositional unity of the book of Isaiah, quite another view emerges.
According to verse 15, for example, when Emanuel is born, “he shall eat curds and honey until he knows to reject the evil and choose the good.” As the author of the book of Isaiah saw it, verse 15 is as much a part of the sign given to Ahaz as verse 14. The sign is not only that a virgin is pregnant with a son, but also that when the son is born, he (and thus Israel as a whole) will be eating “curds and honey.” According to the description of the destruction of Judah in the following verses (Isa 7:17–25), they will be eating “curds and honey,” because the land will have been ruined first by the Assyrians (v. 17), then by the Babylonians (chap. 39), and finally by others after that (chaps. 40–66). Within the whole of the book of Isaiah, the birth of the young Emanuel is located long after the ruin of the Northern and Southern kingdoms.
The nineteenth-century critic Berhard Duhm was so struck by the implications of verse 15 that he could only image it was a late “messianic gloss” to verses 14 and 16. Though I believe Duhm rightly understood the sense of verse 15, his notion that it was a late gloss is rendered unlikely by the presence of the verse in the Qumran Isaiah manuscript. No one here would dispute that the ultimate focus of the book of Isaiah is far beyond the exile, that is, long after the time of Isaiah and Ahaz. According to verse 15, the sign is for that distant future. Isaiah, of course, had a message for Ahaz, but that message was about something that was to happen in the “last days.”
Among other things, the rest of the book of Isaiah is intended as an exegesis of the prophet’s tersely recorded vision in 7:14 and 15. Here we must not only understand the vision, but also the prophet’s exegesis of that vision as it plays out in the remainder of the book.