Exodus 14:31

14:31 When Israel saw the great power that the Lord had exercised over the Egyptians, they feared the Lord, and they believed in the Lord and in his servant Moses.

Exodus 15:25

15:25 He cried out to the Lord, and the Lord showed him a tree. When Moses threw it into the water, the water became safe to drink. There the Lord made for them a binding ordinance, and there he tested them.