The entire Israelite community left the Desert of Sin, moving from place to place as the LORD commanded. They camped at Rephidim, but there was no water to drink.
So the people quarreled with Moses, demanding, "Give us water!" Moses replied, "Why do you quarrel with me? Why do you put the LORD to the test?" But the people, desperate with thirst, grumbled: "Why did you bring us out of Egypt to kill us and our children and livestock with thirst?"
Moses cried out to the LORD, "What am I to do with these people? They are ready to stone me!"
The LORD said, "Go on ahead with some of the elders, and take the staff with which you struck the Nile. I will stand before you on the rock at Horeb. Strike it, and water will flow out for the people to drink." Moses did this before the elders, and the water gushed forth. He named the place Massah and Meribah because the Israelites quarreled there and tested the LORD, saying, "Is the LORD among us or not?"
Then Amalek came and attacked Israel at Rephidim. Moses said to Joshua who was among them, "Choose men and go fight them. Tomorrow I will stand on the hilltop with the staff of God in my hands." Joshua fought, while Moses, Aaron, and Hur went to the hill.
As long as Moses raised his hands, Israel prevailed; but whenever he lowered them, Amalek prevailed. When his arms grew weary, Aaron and Hur placed a stone under him to sit, and they held up his hands—one on each side—so his hands remained steady until sunset. Joshua defeated Amalek with the sword.
The LORD then said, "Write this in a scroll as a memorial and tell it to Joshua: I will utterly blot out the memory of Amalek from under heaven."
Moses built an altar and named it The LORD is my Banner, saying, "Because hands were lifted up to the throne of the LORD, He will be at war with Amalek from generation to generation."