On Purim we celebrate our deliverance from the death decree issued by the Persian prime minister Haman, who was of Amalekite ancestry.

The brief Purim morning Torah reading recounts the original battle between Amalek and the Israelites, waged in the Sinai Desert nearly a millennium before the Purim events.

The Israelites arrive in Rephidim, and are attacked by the Amalekites. Moses charges Joshua to raise an army. On the following day, Joshua led the Israelites into battle, while Moses, Aaron and Hur went to an adjacent hilltop and prayed.

When Moses' arms were raised in prayer, the Israelites would prevail; when he would lower his hands, Amalek prevailed. Aaron and Hur supported Moses' arms until the Israelites defeated their foe.

G‑d commanded Moses to inscribe the story of Amalek's unprovoked attack in a book. "I will surely obliterate the memory of Amalek from beneath the heavens," G‑d said.