Exodus 15:23-25

Living Bible

²³ Arriving at Marah, they couldn’t drink the water because it was bitter (that is why the place was called Marah, meaning “bitter”).

²⁴ Then the people turned against Moses. “Must we die of thirst?” they demanded.

²⁵ Moses pleaded with the Lord to help them, and the Lord showed him a tree to throw into the water, and the water became sweet.

It was there at Marah that the Lord laid before them the following conditions, to test their commitment to him: