Exodus 15:23-27

23And they came to Marah, and could not drink the waters of Marah, for they were bitter; therefore the name of it was called Marah. 24And the people murmured against Moses, saying, What shall we drink? 25And he cried to Jehovah; and Jehovah shewed him wood, and he cast it into the waters, and the waters became sweet. There he made for them a statute and an ordinance; and there he tested them. 26And he said, If thou wilt diligently hearken to the voice of Jehovah thy 1God, and do what is right in his eyes, and incline thine ears to his commandments, and keep all his statutes, I will put none of the complaints upon thee that I have put upon the Egyptians; for I am Jehovah who healeth thee. 27And they came to Elim; and twelve springs of water were there, and seventy palm trees; and they encamped there by the waters.