Amalek is one of the chiefs descended from Eliphaz, firstborn of Esau (Genesis 36:15–16), and thus a great-grandson of Abraham. Amalek’s descendants were mainly desert dwellers, located mostly in the Negev (Numbers 13:29). Amalek is consistently presented as a fierce enemy of Israel, and thus a memory to be blotted out (Exodus 17:14; Deuteronomy 25:19).
The Amalekites have previously appeared in the book of Judges. In Judges 3:13 they had allied with Eglon of Moab.
3 For whenever the Israelites planted crops, the Midianites and the Amalekites and the people of the East would come up against them.