Exodus 15 The bitter waters are sweet

Exodus 15
The bitter waters are sweet
23 And they came to Marah, they could not drink the waters of Marah, for they were bitter: therefore called up your Mara name.
24 And the people murmured against Moses, saying, What shall we drink?
25 And he cried unto the Lord, and the Lord showed him a wood that cast into the waters, and the waters were made sweet: there gave them statutes and his ordination, and there he proved them.
26 And he said, If thou wilt diligently hearken to the voice of the Lord thy God, and obrares what is right in his eyes, and wilt give ear to His commandments and keep all his statutes, none of the diseases I will put on you, I put on Egypt; for I am the Lord who heals you.
27 And they came to Elim, and there were twelve Dágua sources and seventy palm trees: and they encamped there by the waters.