Exodus 17:8-13

And Amalec came, and fought against Israel in Raphidim. And Moses said to Josue: Choose out men: and go out and fight against Amalec. Tomorrow I will stand on the top of the hill having the rod of God in my hand. Josue did as Moses had spoken, and he fought against Amalec: but Moses, and Aaron, and Hur went up upon the top of the hill. And when Moses lifted up his hands, Israel overcame: but if he let them down a little, Amalec overcame. And Moses' hands were heavy; so they took a stone, and put under him, and he sat on it: and Aaron and Hur stayed up his hands on both sides. And it came to pass that his hands were not weary until sunset. And Josue put Amalec and his people to flight, by the edge of the sword.