John Gill Bible Commentary

And Timna was concubine to Eliphaz, Esau's son,.... She is said to be the sister of Lotan, the eldest son of Seir the Horite, Gen 36:22; in Ch1 1:36 mention is made of Timna among the sons of Eliphaz, and of Duke Timnah here, Gen 36:40; and Gerundinsis (y) is of opinion, that Timnah the concubine of Eliphaz, after she had bore Amalek, conceived and bore another son, and she dying in childbirth, he called it by her name to perpetuate her memory: but Jarchi says, that Eliphaz lay with Lotan's mother, the wife of Seir the Horite, of whom was born Timna, and when she grew up she became his concubine, and so was both his daughter and his concubine: and she bare to Eliphaz Amalek; from whence the Amalekites sprung, often mentioned in Scripture, whom the Israelites were commanded utterly to destroy, Sa1 15:18, these were the sons of Adah, Esau's wife; that is, her grandsons. (y) Apud Menasseh ben Israel, conciliator in Gen. Quaest. 57. p. 81.