Êxodo 15:25

25 Then Moses cried out to the Lord, and the Lord showed him a piece of wood. He threw it into the water, and the water became fit to drink. There the Lord issued a ruling and instruction for them and put them to the test.

25 And in answer to his prayer, the Lord made him see a tree, and when he put it into the water, the water was made sweet. There he gave them a law and an order, testing them;