Then Amalek came and fought against Israel at Rephidim.

So Moses said to Joshua, “Choose men for us and go out, fight against Amalek. Tomorrow I will station myself on the top of the hill with the staff of God in my hand.”

Joshua did as Moses told him, and fought against Amalek; and Moses, Aaron, and Hur went up to the top of the hill.

So it came about when Moses held his hand up, that Israel prevailed, and when he let his hand down, Amalek prevailed.

So Joshua overwhelmed Amalek and his people with the edge of the sword.

Then the Lord said to Moses, “Write this in a book as a memorial and recite it to Joshua, that I will utterly blot out the memory of Amalek from under heaven.”

and he said, “The Lord has sworn; the Lord will have war against Amalek from generation to generation.”