15:22So Moses brought Israel from the Red sea, and they went out into the wilderness of Shur; and they went three days in the wilderness, and found no water.

15:23And when they came to Marah, they could not drink of the waters of Marah, for they were bitter: therefore the name of it was called Marah.

15:24And the people murmured against Moses, saying, What shall we drink?

15:25And he cried unto the LORD; and the LORD shewed him a tree, which when he had cast into the waters, the waters were made sweet: there he made for them a statute and an ordinance, and there he proved them,