Exod 15:23 — And 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.
Exod 15:25 — And 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 t