Who Really Wrote the Book of Isaiah?

At least parts of Isaiah were written after the prophet had died. The use of different language style is also a telltale clue.

The Prophet Isaiah, by Michelangelo in the Sistine Chapel.
Buonarroti, Wikimedia Commons

The Book of Isaiah is the first of the three so-called Major Prophets of the Hebrew Bible. It ostensibly records the prophecies of its eponymous hero, Isaiah son of Amoz, of whom we learn very little.

The book itself is mostly made up of prophecies written in obtuse compact poetic Hebrew, and was likely almost as enigmatic at the time of its writing as it is today. Yet these verses include some of the most celebrated in the entire Bible, such as, “they shall beat their swords into plowshares, and their spears into pruning hooks: nation shall not lift up sword against nation, neither shall they learn war any more” (Isaiah 2:4). But who wrote it? 

The King Hezekiah theory

According to tradition first appearing in the Talmud, a compendium of Jewish law redacted in Babylonia at about 500 CE (Bava Batra 14b-15a), the Book of Isaiah was written by King Hezekiah, who reigned from 715 to 686 BCE, and his aides.

How the Jewish sages came to this conclusion is clear. The first verse of the book says that the prophet prophesied during the reigns of four Judean monarchs, the last of whom was Hezekiah. It would make sense that it was the king and his scribes who put together the compilation of Isaiah's prophecies after his death.

Impression of a seal bearing the words "Belonging to Hezekiah [son of] Ahaz king of Judah" and showing a winged sun and ankhs, Assyrian symbols of power and life. Archaeologist Eilat Mazar speculates that the seal was made late in Hezekiah's life, after his recovery from serious illness.
Ouria Tadmor

It would also make sense for a royal archive, if one existed in First Temple Jerusalem, would likely have contained records of prophecies. The royal archives of the Semitic city-state of Mari (in today's Syria) held records of prophecies 1000 years before Hezekiah. The royal archives of the Neo-Assyrian capital Nineveh held records of prophecies too, some written just a few decades after Isaiah's time. Keeping records of prophecies in royal archives may have been the norm.

Still, modern biblical scholars tend to be skeptical. For one thing, the prophecies stored in Mari and Nineveh are practical in nature. For example, if you build this and that structure, it will collapse, or if you attack so and so, you will be victorious and the like. One could imagine why these prophecies would be kept, and verified at a later date. Isaiah's strange prophecies are of another ilk: it is hard to imagine for what practical purpose royal scribes would keep prophecies such as “And I will give children to be their princes, and babes shall rule over them” (3:4). How would they check up on this prophecy to see if it indeed comes to pass?

A bas relief from ancient Nineveh: De Agostini / Getty Images
De Agostini / Getty Images

Isaiah the Younger?

Even if some parts of the book are true representations of the words of Isaiah, certainly major parts of the book are not. This had already been suggested by 12th century Rabbi Abraham Ibn Ezra, who pointed out that the prophesies in chapters 40 to 66, and in chapters 34 and 35, were written in a language very different from the rest of the book, and make no mention of Isaiah in them.

Most modern scholars agree that these chapters cannot be describing prophesies by the original Isaiah, whether written by Hezekiah or not. They had to have been written by someone living after the destruction of Jerusalem in 586 BCE. The original Isaiah lived more than a century earlier, so could not have said “Speak ye comfortably to Jerusalem, and cry unto her, that her warfare is accomplished, that her iniquity is pardoned: for she hath received of the Lord's hand double for all her sins” (40:2.)

These chapters had to have been written by some other prophet living in the context of the Babylonian Exile. Since we do not know his name, scholars refer to him (or, less likely, her) as Second Isaiah or Deutero-Isaiah.

The prophesies in the last 10 chapters of the book (56-66) seem to have been written by yet a third prophet, who lived after the Babylonian Exile, during the early Second Temple period (probably the fifth century BCE). “Even them will I bring to my holy mountain, and make them joyful in my house of prayer: their burnt offerings and their sacrifices shall be accepted upon mine altar; for mine house shall be called an house of prayer for all people“ (56:7), - this for example would not have been written by a prophet living in a time that the Temple lay waste.

Scholars call this prophet Third Isaiah or Trito-Isaiah, though some think the language of Second and Third Isaiah are so similar that they may have been the same person writing before and after the return to Jerusalem.

Apocalypse very soon

And then there are chapters 36 to 39, which are not prophecies at all, but prose accounts of the life of Isaiah.

This section borrows heavily from the Book of Kings, which was written at the very end of the First Temple period. Isaiah 37:6 for example is practically identical to 2 Kings 19:6 and so forth. Clearly, then these must have been tacked on to Isaiah’s prophecies during the Exile at the earliest, probably even later.

Chapters 24 to 27 are also suspect. Many scholars think these chapters were written much later. They espouse an apocalyptic ideology, that is, that the end of times is nigh and God will intervene in the world and punish the wicked and reward the good. That ideology only seems to make an appearance in Jewish literature during the Hellenistic period, starting in the 4th century BCE. Take for example: "Then the moon shall be confounded, and the sun ashamed, when the Lord of hosts shall reign in mount Zion, and in Jerusalem, and before his ancients gloriously” (Isaiah 24:23).

If we take all this together, we can see that the composition of the Book of Isaiah is far more complicated than tradition would suggest.

Possibly some of the verses in the early chapters of the book were indeed said by Isaiah, and taken down by Hezekiah’s scribes, or perhaps by followers of the prophet, who are possibly alluded to in the verse "Behold, I and the children whom the Lord hath given me are for signs and for wonders in Israel from the Lord of hosts, which dwelleth in mount Zion" (8:18). But clearly, much of the book was written much later - during Babylonian Exile and the Second Temple period - by anonymous prophets and scribes.

At any rate, the work achieved something very close to its current form by the 2nd century BCE at the latest, since the library of Qumran – the so-called Dead Sea Scrolls - had manuscripts of Isaiah written in the first century BCE. And since these existed of two different types, one corresponding to the Greek translation and one very close to the Masoretic text, we must assume that the book was already around long enough for variant versions to gradually appear.

A Dead Sea Scroll fragment.