Exodus 17:11-14

11When Moses held up his hand, Israel prevailed. But when he let down his hand, the Amalekites prevailed.

12Moses’ hands grew heavy, so they took a stone, put it under him, and he sat down. Aaron and Hur held up his hands, one on each side. So his hands were steady until the sun went down.

13So Joshua overpowered the Amalekites and his army with the edge of the sword.

14Adonai said to Moses, “Write this for a memorial in the book, and rehearse it in the hearing of Joshua, for I will utterly blot out the memory of the Amalekites from under heaven.”