1 Chronicles 1:38

The sons of Seir This Seir was not Esau, nor of his posterity, but the ancient lord of this country, from whom it had its name, (see Genesis 36:20,) whose genealogy is here set down, that it might be understood from whom Eliphaz's concubine and the mother of Amalek sprung; and because of that affinity which was contracted between his and Esau's posterity. Those who were not united and incorporated with them, were destroyed by them, Deuteronomy 2:12.