During the battle against Amalek, Moses stood on a hilltop with his arms raised, channeling divine power to the Israelite warriors below. But holding your arms up for hours is grueling work, and Moses could not do it alone. Two men stepped forward to support him — Aaron on one side and Chur on the other.
The Mekhilta explains that this was no random arrangement. Aaron represented the tribe of Levi, whose descendants would prove their loyalty by refusing to worship the golden calf. Chur represented the tribe of Judah, whose ancestor would one day lead the Israelites into the Red Sea before it had fully parted — an act of breathtaking faith.
Together, Aaron and Chur held Moses' hands steady, one on each side, until the sun went down and Joshua defeated the Amalekite army in the valley below (Exodus 17:12). The rabbis derived a lasting legal principle from this scene: just as three righteous men stood before God during battle — Moses, Aaron, and Chur — so too, no fewer than three people may officiate before the ark on a public fast day.
What began as a desperate wartime measure became the blueprint for communal prayer. The image endures — one man lifting his hands to heaven, two others holding him steady, all three channeling the merit of their tribes into a single act of intercession.