Exodus 17:13

¹¹And it came to pass, when Moses lifted up his hands, Israel prevailed; and when he let down his hands, Amalek prevailed.

¹²But the hands of Moses were heavy, and they took a stone and put it under him, and he sat upon it; and Aaron and Hur supported his hands one on this side and the other on that, and the hands of Moses were supported till the going down of the sun.

— Exodus 17:13 —

¹⁴And the Lord said to Moses, Write this for a memorial in a book, and speak this in the ears of Joshua; for I will utterly blot out the memorial of Amalek from under heaven.

¹⁵And Moses built an altar to the Lord, and called the name of it, The Lord my Refuge.