Marvin A. Sweeney: No Ancient Manuscript of Isaiah 1-39 Ever Circulated Independent of Isaiah 40-66

While a proponent of the multiple authorship theory of the book of Isaiah, Marvin A. Sweeney noted that:

 

Isaiah 1-39 is part of the whole book of Isaiah, and no ancient manuscript 1-39 circulating independently of 40-66 has ever appeared. The book of Isaiah appears among the Dead Sea Scrolls in a number of manuscripts, but most are fragmentary, except for 1QIsaiah^a, the “Great Isaiah Scroll” from Cave 1, which dates to 125-100 BCE, and 1QIsaiah^b, another Isaiah scroll also from Cave 1, albeit heavily damaged and incomplete, which dates to 50-25 BCE. The Great Isaiah scroll, apparently the oldest and most complete surviving manuscript of the book of Isaiah, is particularly important to us because it divides the book into two portions, Isaiah 1-33 and Isaiah 34-66. (Marvin A. Sweeney, An Introduction to Isaiah 1-39: A Foundational Prophetic Work [Eugene, Oreg.: Cascade Books, 2025], 2-3)