There are a few references to Satan in the Hebrew Bible, but the figure they describe bears little relation to that found in the New Testament and other Christian writings. Yet, according to Philip Jenkins, Christian beliefs about the devil sprang from decidedly Jewish sources. Some of these found their way into the Bibles used by Christian churches:
Probably in the late 3rd century [BCE], the Book of the Watchers (now part of [the Apocryphal book of] 1 Enoch) describes the evil angels who descended to earth to mate with human women, and here we find such later infamous names as Azazel. These are clearly associated with the coming of evil to the earth, a curse cured only by the Great Flood. Also in the late 3rd century, the Book of Tobit features the evil and destructive angel Asmodeus, who was defeated by one of God’s own archangels, Raphael.
A few decades later, the Enochian mythology also appears in the Book of Jubilees, where Mastema (Hostility) fills a role very close to that of the later Satan. Mastema, in fact, is a transitional figure between the divine servant found in Job and the cosmic adversary of New Testament times.