Exodus 17:8-13

8While the people of Israel were still at Rephidim, the warriors of Amalek attacked them.

9Moses commanded Joshua, “Choose some men to go out and fight the army of Amalek for us. Tomorrow, I will stand at the top of the hill, holding the staff of God in my hand.”

10So Joshua did what Moses had commanded and fought the army of Amalek. Meanwhile, Moses, Aaron, and Hur climbed to the top of a nearby hill.

11As long as Moses held up the staff in his hand, the Israelites had the advantage. But whenever he dropped his hand, the Amalekites gained the advantage.

12Moses’ arms soon became so tired he could no longer hold them up. So Aaron and Hur found a stone for him to sit on. Then they stood on each side of Moses, holding up his hands. So his hands held steady until sunset.

13As a result, Joshua overwhelmed the army of Amalek in battle.