Isaiah 1 serves as an introduction to the book as a whole. It announces the subject of the prophecy in the opening verse: “which he says concerning Judah and Jerusalem.” Though this may at first seem a narrow focus, the summoned audience is universal: “Hear, O heavens, and give ear, O earth” (1:2). Echoing the language of Deuteronomy,[1] Isaiah describes the sinfulness of Israel in poetic terms that highlight the depth and destructiveness of their rebellion. Fundamentally, however, “they have despised the Holy One of Israel.” He declares that the nations will overthrow them. He rejects their worship, which is offensive to God since they offer it as unrepentant rebels. The chapter then reaches a climax as Yhwh calls them to repent and promises cleansing and restoration—while threating judgment if they continue to rebel (1:16-20). But Isaiah turns back in verse 21 to describing Judah and Jerusalem’s sinfulness. Once again judgment is declared, but this time it is described as a refining that removes the dross and alloy. God is determined to restore Zion. And yet the contrast between the repentant and the rebel is maintained (1:28). This first chapter, thus sets up the major themes of the book and raises before the reader the question of whether they will be part of the repentant, cleansed, holy people of their holy God or remain rebels who will be consumed by a holy God.
[1] Block, Deuteronomy, NIVAC, 751, n. 22.