Exodus 17:8 - Joseph Benson’s Commentary on the Old and New Testaments

Then came Amalek When they were upon their march from Rephidim to Horeb, (Deuteronomy 25:17-18,) and fought with Israel The Amalekites were the posterity of Esau, who hated Jacob because of the birthright and blessing. They did not boldly front them as a generous enemy, but, without any provocation given, basely fell upon their rear, and smote them that were faint and feeble.