The Holy Scriptures have both a divine origin for their content and a human history for their creation and preservation. The book of the Bible was not originally one unified book, but rather a collection of various books written over time.
The documentary hypothesis is one of the models used by biblical scholars to explain the origins and composition of the Torah. A version of the documentary hypothesis, frequently identified with the German scholar Julius Wellhausen, was almost universally accepted for most of the 20th century.
The Documentary Hypothesis is a theory, also known as JEDP, that states that the first five books of the Bible, called the Pentateuch consisting of Genesis, Exodus, Leviticus, Numbers, and Deuteronomy, were not written completely by Moses but by different authors.
The Documentary Hypothesis—the theory that the Pentateuch was a compilation of selections from several different written documents composed at different places and times over a period of five centuries, long after Moses
It was in the latter half of the nineteenth century that higher criticism began to be taken seriously. These critics rejected Moses as the writer of the Pentateuch, arguing instead that the accounts in Genesis, Exodus, Leviticus, Numbers, and Deuteronomy were based on four other sources [writers] written between the 10th and the 6th centuries B.C.E. To differentiate these sources one from the other, they are simply known as the “J,” “E,” “D,” and “P” sources.