This from notes on the DBH translation of the New Testament:
During the intertestamental period, before the “official” canon of Hebrew scripture was generally established for either Jews or Christians, among the most influential holy texts for both communities were visionary books such as 1 Enoch and Jubilees, which (among many other things) recount the apostasy and punishment of various angels and their offspring in the days after the expulsion of Adam and Eve, and the evils these angelic dissidents visited upon the world—the ultimate consequence of which was the flood, sent by God to rescue the world from the iniquity they had set loose.
The idea of a pre-cosmic fall of the Archangel “Lucifer” or “Satan” was a later development of Christian thought (cf Luke 10:18; 2 Peter 1:19; Revelation 22:6).
In the flood narratives known to the earliest Christians, the only angelic rebellion was that of those “sons of Elohim,” or angels, who, according to Genesis 6:2, were drawn by the beauty of “the daughters of men” to wed them; and according to these texts the mysterious “nefilim” of Genesis 6:6 (understood as monstrous giants) ‘were the children sired by these angels on human women. According to 1 Enoch there were two hundred of these sons of Elohim, or “Watchers,” who abandoned God’s heavenly court, led by a Watcher called Semyaza; they not only became fathers of the nefilim, but taught their human wives to practice sorcery; sorcery; and one of them, Azazel, taught humanity how to make weapons, jewelry, and cosmetics (with predictably dire results).
On being informed of these transgressions by four of his Archangels, God sent the Archangel Michael to imprison the celestial dissidents in the darkness below and to slay the nefilim; but the ghosts of the nefilim then became the demons that now haunt the world.
According to the book of Jubilees, the angels who became enchanted with the beauty of human women were angels of a lower order assigned to govern the natural elements and kinds of this cosmos. In that version of the tale, the celestial angels imprisoned these fallen cosmic angels in the dark below to await the final judgment, while the nefilim were driven to fall upon and kill one another. After the flood, however, the ghosts of the ‘nefilim were still wandering the earth as demons under their leader, Mastema or Beliar (assuming these are the same figure).
When God ordered these bound in prison as well, Mastema prevailed on him to allow a tenth of their number to continue roaming the world till the last day, so as to test humanity and punish the wicked; and thus Mastema comes to serve as “a satan” (that is, an Accuser) in this age, The reference to Christ journeying to these spirits to make his proclamation to them seems to echo the account of Enoch journeying to their abode in order to proclaim God’s condemnation upon them (in chapters 12-15 of 1 Enoch).
During the intertestamental period, before the “official” canon of Hebrew scripture was generally established for either Jews or Christians, among the most influential holy texts for both communities were visionary books such as 1 Enoch and Jubilees, which (among many other things) recount the apostasy and punishment of various angels and their offspring in the days after the expulsion of Adam and Eve, and the evils these angelic dissidents visited upon the world—the ultimate consequence of which was the flood, sent by God to rescue the world from the iniquity they had set loose.
The idea of a pre-cosmic fall of the Archangel “Lucifer” or “Satan” was a later development of Christian thought (cf Luke 10:18; 2 Peter 1:19; Revelation 22:6).
In the flood narratives known to the earliest Christians, the only angelic rebellion was that of those “sons of Elohim,” or angels, who, according to Genesis 6:2, were drawn by the beauty of “the daughters of men” to wed them; and according to these texts the mysterious “nefilim” of Genesis 6:6 (understood as monstrous giants) ‘were the children sired by these angels on human women. According to 1 Enoch there were two hundred of these sons of Elohim, or “Watchers,” who abandoned God’s heavenly court, led by a Watcher called Semyaza; they not only became fathers of the nefilim, but taught their human wives to practice sorcery; sorcery; and one of them, Azazel, taught humanity how to make weapons, jewelry, and cosmetics (with predictably dire results).
On being informed of these transgressions by four of his Archangels, God sent the Archangel Michael to imprison the celestial dissidents in the darkness below and to slay the nefilim; but the ghosts of the nefilim then became the demons that now haunt the world.
According to the book of Jubilees, the angels who became enchanted with the beauty of human women were angels of a lower order assigned to govern the natural elements and kinds of this cosmos. In that version of the tale, the celestial angels imprisoned these fallen cosmic angels in the dark below to await the final judgment, while the nefilim were driven to fall upon and kill one another. After the flood, however, the ghosts of the ‘nefilim were still wandering the earth as demons under their leader, Mastema or Beliar (assuming these are the same figure).
When God ordered these bound in prison as well, Mastema prevailed on him to allow a tenth of their number to continue roaming the world till the last day, so as to test humanity and punish the wicked; and thus Mastema comes to serve as “a satan” (that is, an Accuser) in this age, The reference to Christ journeying to these spirits to make his proclamation to them seems to echo the account of Enoch journeying to their abode in order to proclaim God’s condemnation upon them (in chapters 12-15 of 1 Enoch).