Amongst biblical scholars there is broad agreement that the Book of Isaiah was not written all at once, or by one person. There is good internal evidence that the writing of the book spanned more than a generation (I’ve discussed some of the evidence here). For example, the prophet Isaiah is mentioned several times in the first 39 chapters, but never thereafter, and the events described in these chapters – such as the Assyrian seige of Jerusalem – are set more than a century before the events in the remainder of the book.
This is not a new idea. Since German Protestant theologian Johann Gottfried Eichhorn (1752-1827) proposed it Christian scholars have argued that Isaiah 40-66 was written during the Babylonian exile . However, long before Eichhorn, the 11th century Jewish scholar Rabbi Moses ben Samuel haKohen ascribed Isaiah 40-66 to a Second Temple period prophet, i.e. after the return from exile. The great majority of biblical scholars now accept that “Isaiah” is made up of at least two different books, and probably three. Since Eichhorn several scholars have noted that there seems to be a clear break between the end of chapter 55 and the beginning of 56, that the last eleven chapters of Isaiah (56-66) have a different “style” and structure to the earlier chapters, and they refer to the Temple and sacrifices in such a way that it sounds like the Temple had been rebuilt and sacrifices were being carried out again. This would date these chapters to the period after the return from exile in Babylon and the rebuilding of Jerusalem and the Temple. Some scholars think these chapters were written by the same person who wrote “Second Isaiah” (chapters 40-55) upon his return from Babylon to the Land, while others argue they were written by someone else – a “Third Isaiah” (or Trito-Isaiah).
This “Third Isaiah” – chapters 55 to 66 – looks like it could be a collection of speeches by one or more prophets, raising the possibility that there was no single author, or that an “editor” put it together at some later date. This could explain why at some points the speaker refers to the Temple as though it has been rebuilt (e.g. 56:7), while at other times he speaks as though the rebuilding is still a work in progress (e.g. 61:4), or even still in ruins (e.g. 64:10-11). There is little doubt that the scholarly jury is still out on whether there were two or three Isaiahs (few would argue these days that there was only one writer for the whole of Isaiah 1-66), and there is no consensus on when each of the major sections of the book were written. I am personally inclined to the view that Isaiah comprises three separate works – First, Second and Third Isaiahs – although I readily confess that I am not an Isaiah expert and my opinion is open to change if and when I do more work on Isaiah.
[By the way, if you’re wondering if prophet Isaiah in the painting is writing in ‘proper’ Hebrew or squiggles, it looks to me like he’s writing in Latin!]