As Joshua fought the Amalekites, stationed on a nearby hill were Moses, Aaron, and Hur. The Israelites proved superior in battle when Moses raised his hands.
وَعِنْدَمَا كَانَ مُوسَى يَرْفَعُ يَدَيْهِ ،‏ كَانَ ٱلْإِسْرَائِيلِيُّونَ يَغْلِبُونَ فِي ٱلْمَعْرَكَةِ .‏