Exodus 17:10-13 CEV
[10] Joshua led the attack as Moses had commanded, while Moses, Aaron, and Hur stood on the hilltop. [11] The Israelites out-fought the Amalekites as long as Moses held up his arms, but they started losing whenever he lowered them. [12] After a while, his arms were so tired that Aaron and Hur got a rock for him to sit on. Then they stood beside him and supported his arms in the same position until sunset. [13] That's how Joshua defeated the Amalekites.