And it came to pass, when Moses held up his hand, that Israel prevailed: and when he let down his hand, Amalek prevailed. But Moses hands were heavy; and they took a stone, and put it under him, and he sat thereon; and Aaron and Hur stayed up his hands. Exodus 17:11
Trivia: Just before God appeared to Moses on Mount Sinai, what were Moses's instructions to the male Israelites?
