Exodus 15:23-25

Holman Christian Standard Bible

²³ They came to Marah, but they could not drink the water at Marah because it was bitter—that is why it was named Marah.^{[a] 24} The people grumbled to Moses, “What are we going to drink?”^{(A) 25} So he cried out to the Lord, and the Lord showed him a tree. When he threw it into the water, the water became drinkable.

He made a statute and ordinance for them at Marah and He tested them there.^(B)