Exodus 15:23

And they came to Merrha, and could not drink of Merrha, for it was bitter; therefore he named the name of that place, Bitterness.

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.

When they came to Marah, they couldn’t drink from the waters of Marah, for they were bitter. Therefore its name was called Marah.