Exodus 17:13-16

17:13 So Joshua destroyed Amalek and his army with the sword.

17:14 The Lord said to Moses, “Write this as a memorial in the book, and rehearse it in Joshua’s hearing; for I will surely wipe out the remembrance of Amalek from under heaven. 17:15 Moses built an altar, and he called it “The Lord is my Banner,” 17:16 for he said, “For a hand was lifted up to the throne of the Lord – that the Lord will have war with Amalek from generation to generation.”