J, or the Yahwistic source (in German, Jahwistic), is named for its assumption that the divine name, YHWH (often vocalized Yahweh), was known from the beginning of time (Genesis 4:26). E, or the Elohistic source, is so named because it insists that God was known as Elohim until the tetragrammaton was revealed to Moses (Exodus 3:15). P, the Priestly source, is distinguished for its interest in the priesthood and in ritual law. D, the Deuteronomic source, makes up most of the Book of Deuteronomy. See Victor Hurowitz, “P—Understanding the Priestly Source,” BR 12:03; Moshe Weinfeld, “Deuteronomy’s Theological Revolution,” BR 12:01.