Jubilees 48:15
14 All of the people whom he brought out to pursue the Israelites, the Lord our God threw into the sea — to the depths of the abyss — in place of the Israelites, just as the Egyptians had thrown their sons into the river. He took revenge on 1,000,000 of them. One thousand men who were strong and also very brave perished for one infant of your people whom they had thrown into the river. 15 On the fourteenth day, the fifteenth, the sixteenth, the seventeenth, and the eighteenth the prince of Mastema was bound and locked up behind the Israelites so that he could not accuse them. 16 On the nineteenth day we released them so that they could help the Egyptians and pursue the Israelites.
Jubilees 49:2
1 Remember the commandments which the Lord gave you regarding the Passover so that you may celebrate it at its time on the fourteenth of the first month, that you may sacrifice it before evening, and so that they may eat it at night on the evening of the fifteenth from the time of sunset. 2 For on this night — it was the beginning of the festival and the beginning of joy — you were eating the Passover in Egypt when all the forces of Mastema were sent to kill every firstborn in the land of Egypt — from the pharaoh’s firstborn to the firstborn of the captive slave-girl at the millstone and to the cattle as well. 3 This is that which the Lord gave them: into each house on whose door they saw the blood of a year-old lamb, they were not to enter that house to kill but were to pass over it in order to save all who were in the house because the sign of the blood was on its door.
Notes and References
"... As often in the book, the narrator speaks of the role of “the angel Mastema,” the Satan-like figure who leads the forces of evil. Here, Mastema tries to kill Moses, then, failing that, seeks to aid Pharaoh’s magicians in combating the ten plagues, and still later urges the Egyptians to pursue the departing Israelites - in short, Mastema does everything he can to foil God’s plan to free the Israelites. He actually has to be held in restraints for five days, “bound and locked up” (Jubilees 48:15), to prevent him from succeeding. By contrast, in chapter 49 - largely taken up with detailing the laws of Passover and full of the “terminology of the Heavenly Tablets”—the narrator suddenly reminds Moses of what happened on the fateful night that inaugurated the exodus ... Here, there is a clear about-face: instead of trying to frustrate God’s plans, Mastema’s legions actually become God’s agents, carrying out the tenth plague instead of opposing it ..."
Kugel, James L. A Walk through Jubilees: Studies in the Book of Jubilees and the World of Its Creation (p. 229) Brill, 2012