Isaiah, Book of

The Book of Isaiah is the longest of the prophetic books and the most frequently quoted in the New Testament, standing at the head of the Major Prophets. Its sixty-six chapters fall naturally into two major sections: chapters 1–39, dominated by oracles of judgment against Judah, Israel, and the surrounding nations, punctuated by historical narratives from Hezekiah's reign; and chapters 40–66, which shift to consolation, restoration, and the vision of a new exodus and new creation. The transition at chapter 40 — "Comfort, comfort my people" — is among the most famous passages in the Hebrew Bible and is quoted in all four Gospels as the introduction to John the Baptist's ministry (Matthew 3:3; Mark 1:3; Luke 3:4; John 1:23).

The question of the book's authorship has been central in modern biblical scholarship. Traditional interpretation ascribes the entire book to the eighth-century prophet Isaiah son of Amoz. Critical scholarship since the eighteenth century has argued that chapters 40–55 ("Deutero-Isaiah") and 56–66 ("Trito-Isaiah") reflect a later period, with chapters 40–55 addressing the Babylonian exile by name (Isaiah 44:28; 45:1). The New Testament cites both halves of the book under the name Isaiah (John 12:38–41), supporting the unity of the book's canonical witness. Isaiah's servant songs (42:1–4; 49:1–6; 50:4–9; 52:13–53:12) are the most christologically rich texts in the Old Testament.