Exodus 15:25-26

So Moses cried out in prayer to GOD. GOD pointed him to a stick of wood. Moses threw it into the water and the water turned sweet. That’s the place where GOD set up rules and procedures; that’s where he started testing them. GOD said, “If you listen, listen obediently to how GOD tells you to live in his presence, obeying his commandments and keeping all his laws, then I won’t strike you with all the diseases that I inflicted on the Egyptians; I am GOD your healer.”