Then the LORD said to Joshua, "Point your spear at Ai; I am giving it to you." Joshua did as he was told,

As long as Moses held up his arms, the Israelites won, but when he put his arms down, the Amalekites started winning.

When Moses' arms grew tired, Aaron and Hur brought a stone for him to sit on, while they stood beside him and held up his arms, holding them steady until the sun went down.