Where in the Bible does it tell you that Isaiah has 66 chapters?

Answer 1

The Bible itself does not mention chapters, because the books that form the Bible were originally written without chapters. They were divided into present-day chapters by Stephen Langton about 1200 CE, and of course the number of chapters in Isaiah was based on his own judgement. The book of Isaiah is now considered by most scholars to be composite, written by either two or three authors over a period of around two hundred years.

• Chapters 1-39 contain, with numerous additions, the work of Isaiah of Jerusalem, called I Isaiah, First Isaiah or Proto-Isaiah.
• Chapters 40-55 record the words of an anonymous author during the Babylon Exile. This author is now called II Isaiah, Second Isaiah or Deutero-Isaiah.
• Some scholars consider chapters 56-66, which are from the post-Exilic period, to be a continuation of the work of Deutero-Isaiah, while others attribute them to another anonymous author now called III Isaiah, Third Isaiah or Trito-Isaiah.