And he cried to the LORD, and the LORD showed him a log, and he threw it into the water, and the water became sweet. There the LORD made for them a statute and a rule, and there he tested them,
25. And he cried. Hence we gather that Moses alone duly prayed when the people tumultuously rose against him, and that they who were not worthy of the common air itself were abundantly supplied with sweet water. Herein shone forth the inestimable mercy of God, who deigned to change the nature of the water for the purpose of supplying such wicked, and rebellious, and ungrateful men.
It should seem, it was with some difficulty that Moses prevailed with Israel to leave that triumphant shore on which they sang the foregoing song. They were so taken up with the sight, or with the song, or with the spoiling of the dead bodies, that they cared not to go forward, but Moses with much ado brought them from the Red Sea into a wilderness.
Commenting on Exodus 15:22-27
And said, if thou wilt diligently hearken to the voice of the Lord thy God,.... By this and the following words, they are prepared to expect a body of laws to be given unto them, as the rule of their future conduct; and though they were delivered from the rigorous laws, bondage, and oppression of the Egyptians, yet they were not to be without law...