Modern biblical scholarship has historically divided Isaiah into two or three parts. Chapters 1-39 tend to be viewed as the oldest portion and the portion that has the largest sections that were likely to have actually been composed by the prophet Isaiah in the 8th century BCE (sometimes referred to as Proto-Isaiah).  Chapters 40-66 are commonly referred to as Deutero-Isaiah (Deutero here means “second), or sometimes they are divided into Deutero-Isaiah (ch 40-55) and Trito-Isaiah (ch 56-66). Typically when preparing for one of these background blog posts, I do so by reading the introductory essay in the New Interpreter’s Bible, which is usually a 10-15 page essay by scholars with relevant expertise that describes the major theories about when, where, and by whom the book was composed, relevant historical events, and major themes.  The division between Proto-Isaiah and Deutero-Isaiah is both stark enough and well established enough that the relevant volume of the New Interpreter’s Bible has one introduction to Proto-Isaiah and a second introduction to Deutero-Isaiah (which for them is the more expansive ch 40-66 version).¹

The basic reason for this division is that Proto-Isaiah, for example, refers to events that can be dated to the 8th century BCE (chapters 7-8 are viewed as referring to Syro-Ephraimitic War which is dated to 735-732 BCE, chapters 28-33, 36-39 are viewed as referring to issues with Hezekiah and Assyria dated to 701 BCE), whereas Deutero-Isaiah refers to the reign of the Persian emperor Cyrus (600-530 BCE).  This means that there are perhaps 200 years separating the earliest parts of Isaiah from the latest parts of Isaiah.  Remember, we saw something similar when we looked at the composition of Zechariah, in which the first part of Zechariah was clearly dated to the end of the Babylonian exile under Person reign, whereas the second part was later and more ambiguously dated. 

The sort of scholarly analysis that has led to both Zechariah and Isaiah being divided into multiple parts, which are assumed to have different dates of composition and authors, is called redaction criticism and has been employed for most of the book is Hebrew Scripture.  For most of Hebrew Scripture, the scholarly consensus is that there has been an extensive editorial process over a period of many centuries, wherein multiple older sources are combined with each other or newer material, changes are made to create a more unified whole, changes are made to bring the text more closely in line with the prevailing religious sentiment of the authors, and so on.  

If you read scholarly works that seriously debate the redactional history of a given piece of Scripture, what you will find is that the scholarly debate becomes quite fine-grained and pedantic quite quickly, and the dispute between different scholars about which specific sentences or phrases belong to which specific redaction is obviously impossible to resolve because they are advancing hypotheses that cannot possibly be tested or conclusively resolved. 

Isaiah is not different on this account, and the introductions to both Proto-Isaiah and Deutero-Isaiah take care to emphasize that although the Proto/Deutero/Trito-Isaiah division has been viewed as a valid division for more than a century, the actual history of redaction is much more complicated than that (Proto-Isaiah, for example, has at least some passages that were likely added as late as the latest passages in Deutero/Trito-Isaiah). 

Generally speaking, my take on redaction criticism is this: it is important to know that the various books of the Bible have an editorial history, and knowing at least the broad strokes of that history is helpful when reading a given book. Partly, this is because it makes it easier to line up what would otherwise be inscrutable passages with historical events and thus to have a clearer understanding of their meaning. Most importantly, though, redaction criticism highlights the ways in which communities of the faithful separated by centuries have been in conversation with each other.

This is the other point that the introduction to Proto-Isaiah and Deutero-Isaiah take care to make. Apparently scholarly fashions have shifted and rather than emphasizing the differences in composition of each part, there is a renewed emphasis on Isaiah as a unified work. Great care was taken to preserve, edit, rearrange, and recompose the book of Isaiah over centuries, and the material eventually included apparently was viewed as a thematic whole. 

This attitude is helpful for our purposes as well, and although I think it is important to remember that there is a division between (mostly) earlier and (mostly) later parts, ultimately the reason that we are investigating the text of this book more thoroughly is that even for early Christians, centuries after the latest editorial changes to the book of Isaiah, it is one of the most-cited texts in the New Testament, and its vision clearly shaped early Christians’ understanding of Jesus.  

Because of the size of Isaiah as well as the number of citations, this will likely be our focus for quite some time so I hope you are as excited about digging into the text as I am!

1.  For the most part this post is summarizing the information in those two introductions. ↩︎