8 Then Amalek came and fought with Israel in Rephidim. 9 And Moses said unto Joshua, Choose us out men and go out, fight with Amalek; tomorrow I will stand on the top of the hill with the rod of God in my hand. 10 So Joshua did as Moses had said to him and fought with Amalek; and Moses, Aaron, and Hur went up to the top of the hill. 11 And it came to pass, when Moses held up his hand, that Israel prevailed; but when he let down his hand, Amalek prevailed. 12 And Moses’ hands were heavy, so they took a stone and put it under him, and he sat upon it; and Aaron and Hur stayed up his hands, the one on the one side and the other on the other side; thus his hands were steady until the going down of the sun. 13 And Joshua disabled Amalek and his people with the edge of the sword.
14 And the LORD said unto Moses, Write this for a memorial in the book and tell Joshua that I must utterly blot out the remembrance of Amalek from under heaven. 15 And Moses built an altar and called the name of it The LORD is my Banner, {YHWH-nissi} 16 for he said, Because Amalek lifted his hand against the throne of the LORD, the LORD will have war with Amalek from generation to generation.