The Battle with Amalek at Rephidim

At Rephidim, Amalek arrived and fought against Israel. In response to this attack, Moses commanded Joshua to choose men and go out to fight with Amalek the following day (Exodus 17:8-9). Moses stated that he would stand on the top of the hill holding the staff of God in his hand. Joshua did as Moses commanded and engaged Amalek in battle, while Moses, Aaron, and Hur ascended to the top of the hill (Exodus 17:10).

The text records that whenever Moses held up his hand, Israel prevailed, but when he let down his hand, Amalek prevailed. As Moses' hands grew heavy, Aaron and Hur took a stone and put it under him so he could sit on it. Aaron and Hur then stayed up his hands, one on one side and the other on the other side, so that his hands were steady until the going down of the sun (Exodus 17:11-12). Through this action, Joshua overwhelmed Amalek and his people with the edge of the sword.

Following the victory, the Lord instructed Moses to write this event as a memorial in a book and rehearse it in the ears of Joshua, stating that He would utterly put out the remembrance of Amalek from under heaven (Exodus 17:14). Moses built an altar there and named it YHWH-Nissi, which means 'The Lord is my banner'. He declared that because the Lord has sworn, the Lord will have war with Amalek from generation to generation (Exodus 17:15-16).