Exodus 15:25

The Lord shewed him a tree] There are certain plants whose bark and leaves are employed to sweeten bitter water. Lesseps mentions a kind of thorn found in the desert possessing anti-saline properties. Here, as in the case of the Plagues in Egypt, the miracle was effected by means of a natural agent. The miracle consisted in God's directing Moses at this particular juncture to the use of the right means. The tree would not have been employed had it not possessed the property required. He made for them a statute] The subject is most probably God, not Moses. God used this occasion to teach the people that such troubles as the present were intended to 'prove' them, i.e. to test their loyalty to Him, and that if they stood the test He would protect and provide for them.