Exodus 2:16

2:16 Now a priest of Midian had seven daughters, and they came and began to draw water and fill the troughs in order to water their father’s flock.

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.