The overall unity of Isaiah
A description of the lengthy process that resulted in the book of Isaiah should not leave the impression that it is simply a collection of fragments, or an anthology whose parts have no organic relation to each other. The unity of the book comes in large part from the development and deepening of major themes: the centrality of Jerusalem; the importance of the “anointed” ruler; and the contrast between God's people and the political and military machinations of the great world empires. The image of Jerusalem in later books of the Bible, particularly in the book of Revelation in the New Testament, cannot be fully understood without grasping the development of the idea of Jerusalem in Isaiah. The image of a new ruler who will usher in a new age of justice, righteousness, and peace, and its development into the concept of a “messiah” in early Jewish and early Christian writings, also cannot be fully appreciated without an understanding of how Isaiah developed the concept of the anointed ruler from its historical reality as the Davidic line of Judean rulers to the hoped‐for restoration of an idealized king for a purified nation. And the notion of God's people surviving and triumphing even when all of the world's great powers are arrayed against them echoes in the later writings of the Hebrew Scriptures, in the Jewish writings contained in the Apocryphal/Deuterocanonical Books, and in the New Testament.