Exodus 15:23-25 ▼

23 And they came to Marah, but they could not drink the waters of Marah, for they were bitter; therefore it was named Marah.

24 So the people grumbled at Moses, saying, “What shall we drink?”

25 Then he cried out to Yahweh, and Yahweh showed him a tree; and he threw it into the waters, and the waters became sweet. There He set for them a statute and a judgment, and there He tested them.