23 When they came to Marah, they could not drink its water because it was bitter. (That is why the place is called Marah. ) 24 So the people grumbled against Moses, saying, “What are we to drink?”
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.