Investigation: One Isaiah or Several?

"The vision of Isaiah the son of Amoz, which he saw concerning Judah and Jerusalem in the days of Uzziah, Jotham, Ahaz, and Hezekiah, kings of Judah" (1:1). The heading covers roughly 740 to 700 BC. Chapters 1–39 are full of that world: Ahaz and the Syro-Ephraimite war (7), Assyria as God's rod (10), Sargon's capture of Ashdod (20), Sennacherib at the gates (36–37).

Then the setting changes. "Comfort ye, comfort ye my people… her warfare is accomplished" (40:1–2). Jerusalem's punishment is over; Babylon's gods are carried off (46:1–2); Cyrus is named twice, "my shepherd" (44:28) and "his anointed" (45:1), as the one who will rebuild Jerusalem. Chapters 56–66 seem to address a community back in the land, arguing about temple, sabbath, fasting and who belongs.

The book itself speaks of preserving the prophet's words: "Bind up the testimony, seal the law among my disciples" (8:16); "write it before them in a table, and note it in a book, that it may be for the time to come for ever and ever" (30:8). A prophet's words were kept, written and handed on by others. The question is how much of the book came from that process.

Ancient readers knew the book as one. Ben Sira, about 180 BC, says Isaiah "saw by an excellent spirit what should come to pass at the last, and he comforted them that mourned in Sion" (Sirach 48:24), joining the prophet of Hezekiah's time with the comfort of chapter 40. The Great Isaiah Scroll copies chapters 1–66 as one continuous book. The New Testament cites passages from all parts under Isaiah's name.

Signs of growth inside 1–39

Even scholars who date most of 1–39 to the 8th century see later material there: 13:1–14:23 (Babylon as the great enemy, with the Medes, 13:17), chapters 24–27 (often called the "Isaiah Apocalypse"), and 34–35 (whose highway and blooming desert sound like chapter 40). Isaiah 2:2–4 also appears in Micah 4:1–3. The prose story of chapters 36–39 is almost word for word 2 Kings 18:13–20:19, with Hezekiah's psalm (38:9–20) added in Isaiah. Each of these is evidence for editing; none dates itself.

Signs of unity

"The Holy One of Israel" is a favorite title in every part of the book (1:4; 5:19; 12:6; 30:11; 41:14; 43:3; 54:5; 60:9, among about 25 uses) and rare elsewhere. Themes run through all of it: Zion, the remnant, blindness and deafness (6:9–10; 29:18; 35:5; 42:18–19), the highway (11:16; 35:8; 40:3; 62:10), nations streaming to Jerusalem (2:2–4; 60; 66:18–23). Defenders of one author read these as one mind; defenders of several read them as a school or editors deliberately binding the book together.

What the Great Isaiah Scroll shows and does not show

1QIsa-a (c. 125 BC) runs from 1:1 to 66:24 in one scroll. Scholars report no special break marking chapter 40 as the start of a new book. They have also reported a gap of about three lines at the foot of the column that ends chapter 33, before chapter 34 starts a new column, and some proposed that the book was once copied in two halves (W. H. Brownlee). The scroll proves that the 66-chapter book existed by the 2nd century BC. It cannot show how the book came to be.

Predictive prophecy and the dating question

The Cyrus texts are central. If an 8th-century prophet named a Persian king about 150 years before his birth, the text is predictive prophecy of an unusual kind (compare 1 Kings 13:2, where Josiah is named ahead of time). Scholars who date 40–48 to about 545–539 BC point to the way the text argues from Cyrus's present success (41:2–4, 25; 45:1–4) and to its addressing exiles as its hearers. Traditional readers answer that God's knowledge of the future is a theme of these very chapters ("declaring the end from the beginning," 46:10; 44:24–28). History can test the setting a text assumes; it cannot test whether God revealed the future. The site states both and decides neither.

"Three Isaiahs" is a shorthand

"First, Second and Third Isaiah" (or Deutero- and Trito-Isaiah) are modern labels for parts of the book, not names of known people. Many scholars now prefer "Isaiah 1–39, 40–55, 56–66" and speak of a long process of composition and editing rather than three single authors. Some date most of 56–66 to the same author as 40–55; some see the editors of 40–66 reshaping 1–39 too. "Academics proved three authors" is not an accurate summary of the field.