Work by scholars from the late 19th century had established that five sources lay behind the Pentateuch. They came to be known by letters: J, E, P, and D. These theories were a mainstay of biblical studies until recently. Although questioned in the past 20 years, the theory known as the Documentary Hypothesis is still accounted a firm starting place for any sort of examination of the text of the Pentateuch. I also find out why the Bible is divided into chapters and verses.