Scholars have identified three literary traditions in Exodus, designated by the letters J, E, and P. The J strand, so called because it uses the name Yahweh (Jahweh in German) for God, is a Judaean rendition of the sacred story, perhaps written as early as 950 BCE.
The E strand, which designates God as Elohim, is a version of the sacred story from the northern kingdom of Israel, written in about 900–750 BCE.
The P strand, so called because of its cultic interests and regulations for priests, is usually dated in the 5th century BC and is regarded as the law upon which Ezra and Nehemiah based their reform. Each of these strands preserves materials much older than the time of their incorporation into a written work. Exodus thus conserves extremely old oral and written history. (See also Torah.)