Exodus 15:22-27 - Yahweh Provides Water At Marah
22 Then Moses led Israel from the Reed Sea and they went to the desert of Shur. They traveled into the desert for three days and did not find water. 23 When they came to Marah, they could not drink the water at Marah because it was bitter. (That is why it's called Marah.) 24 Then the people complained against Moses: "What are we to drink?" 25 Moses cried out to the LORD, and the LORD showed him a tree, which he threw into the water, and the water became sweet. 26 There the LORD presented to them a statute and an ordinance, and there he tested them. He said, "If you will carefully obey the LORD your God, do what he sees to be right, listen to his commandments, and keep all his statutes, then I won't inflict on you all the diseases that I inflicted on the Egyptians, because I am the LORD your healer."
27 Then they came to Elim where there were twelve springs of water and 70 palm trees, and they camped there by the water.