When was Isaiah written?
Isaiah's book does not announce a publication date. It gives something better: a list of four kings whose reigns fixed the years the prophet worked, and a handful of events inside the book that can be pinned to a moment.
The Span Named in the First Verse
The opening line ties the whole book to the reigns of Uzziah, Jotham, Ahaz and Hezekiah, kings of Judah. That gives a working range rather than a single year:
Morrish Bible DictionaryNothing more is known of the ancestors of Isaiah than that he was the son of Amoz. He prophesied in the days of Uzziah, Jotham, Ahaz, and Hezekiah, all kings of Judah. From the closing years of Uzziah to the death of Hezekiah would be from about B.C. 765 to 700, a period of 65 years.
Others give slightly different figures for the same reigns — Uzziah's rule beginning around 767 BC and Hezekiah dying around 697 BC — so the numbers should be read as close estimates, not exact dates.
A Book Written Across a Career
Because the ministry stretched over four reigns, the book was composed piece by piece over decades. Its position in history also shapes what it contains:
The Bible TreasuryOf the four greater prophets — Isaiah, Jeremiah, Ezekiel and Daniel — the first named is the only one who worked before the ten tribes were deported to Halah and Habor, by the river of Gozan, and to the cities of the Medes... Beginning with the reign of Uzziah, and going on to that of his great-grandson Hezekiah, Isaiah must have worked for half a century or perhaps more.
Few Fixed Dates Inside
Isaiah rarely stamps a date on his own chapters. That habit sets him apart from other writing prophets:
The Bible TreasuryOf dates we have but few, so different from the habit of Jeremiah and Ezekiel. The death of Uzziah (Isa. 6) and of Ahaz (Isa. 14:28), the invasion of Judah by Pekah and Rezin (Isa. 7), and later by Sennacherib (Isa. 36), and the capture of Ashdod by Tartan, sent there by Sargon king of Assyria (Isa. 20), are all that the prophet has noted.
Where a date is missing, the reign named at the head of a section still supplies the setting:
J. N. DarbyIn general the prophets date their prophecies from the name of the kings during whose reign they prophesied. One always finds in their writings something which gave rise to their prophecy.
Isaiah Wrote More Than This Book
Scripture records another piece of writing from the same hand, which shows he was active as a writer during Uzziah's reign as well:
C. Knapp"Now the rest of the acts of Uzziah, from first to last, Isaiah the prophet the son of Amoz wrote"... It was "in the year that King Uzziah died" that Isaiah entered upon his full prophetic ministry. The moral condition of the nation during the close of Uzziah's reign is revealed in the first five chapters of his prophecy. He was also the historian of that reign.
The Dispute Over a Second Author
The real argument about dating is not about the century but about how many hands wrote the book. Commentators here reject the theory of multiple authors and trace when it appeared:
Arno Clemens GaebeleinThey tell us that the book of Isaiah is of a composite origin. Isaiah did not write the entire book which bears his name. For about 2,500 years no one ever thought of even suggesting that Isaiah did not write the book. Then they invented an unknown person called the Deutero-Isaiah — a second Isaiah — who is said to have written the sublime chapters 40-66.
Two lines of evidence are offered against a later date for the closing chapters. One is the vocabulary that runs through both halves:
F. B. HoleIn the Old Testament God is spoken of as "The Holy One of Israel" only about 37 times. Just 30 of these occur in Isaiah, so it is the characteristic title of God in his book. These 30 are almost equally divided between chapters 1-39 and 40-66, occurring 14 times in the first part and 16 times in the second. This strongly supports unity rather than plurality of authorship.
The other is the way the New Testament handles the book, quoting from each half and naming Isaiah both times.
H. J. VineIn John 12:37-43, both parts are strikingly linked together as the word of Isaiah, pointing to Christ.
Why the Late Date Was Proposed
The pressure to move chapters 40-66 forward came largely from one detail — Cyrus is named roughly two centuries before he ruled:
Arend RemmersThe mentioning of Cyrus' name long before his time is one out of hundreds of examples in the Word of God proving that God declares the end from the beginning (Is. 46:10)... The man of God out of Judah mentioned the name of King Josiah in front of King Jeroboam around 300 years before he ever lived (1 Kings 13:2).
Summary
- Reigns. The book is dated by kings, not calendars: Uzziah, Jotham, Ahaz and Hezekiah — roughly 765 to 700 BC.
- Length. Those four reigns mean around 65 years of service, so the book grew across a lifetime rather than one sitting.
- Landmarks. Isaiah fixes only a few moments — Uzziah's death, Ahaz's death, the invasions by Pekah and by Sennacherib, the fall of Ashdod.
- Author. One writer is held throughout; the shared title "the Holy One of Israel" and the New Testament's quoting of both halves under his name are the evidence given.
- Objection. The late-date theory rests mainly on Cyrus being named early — which the writers treat as prophecy working exactly as prophecy should.