The Israelites are complaining again, this time about not enough water. So Moses complains to God who tells him to strike a rock and water will flow from it.
Then the Amalekites come to attack the Israelites at Rephidim. Moses tells Joshua to fight while he goes to the top of a hill. Aaron and Hur go with Moses. As long as Moses keeps his hands and staff raised the Israelites win the battle. Aaron and Hur helped him hold his hands up until Joshua defeated the Amalekites and God declares that he will commit genocide against them.
Again with the complaining. Doesn’t God know that people need water? And have the Israelites not figured out who is taking care of them?
As for the fighting, I imagine any fighting would kill at least some of God’s people. He saved everyone one of them from the Pharaoh only to let some die in a dessert battle with another tribe or clan or something? Wasn’t God supposed to be following as a pillar of fire? Did the Amalekites think they could defeat the multitudes of people who had a pillar of fire guarding them?