Exodus 15:22-27

22Then Moses led Israel to journey away from the Red Sea. They went out to the Desert of Shur, walked for three days into the desert, and found no water.

23Then they came to Marah, but they were not able to drink the waters of Marah, because they were bitter. (That is why its name was Marah.)

24So the people murmured against Moses, saying, “What can we drink?”

25He cried out to the Lord, and the Lord showed him a tree. When Moses threw it into the water, the water became safe to drink. There the Lord made for them a binding ordinance, and there he tested them.

26He said, “If you will diligently obey the Lord your God, and do what is right in his sight, and pay attention to his commandments, and keep all his statutes, then all the diseases that I brought on the Egyptians I will not bring on you, for I, the Lord, am your healer.”

27Then they came to Elim, where there were twelve wells of water and seventy palm trees, and they camped there by the water.