4 Then the Lord said to Moses, "Reach out your hand and take it by the tail" (and he reached out his hand and caught it, and it became a rod in his hand), 5 "that they may believe that the Lord God of their fathers, the God of Abraham, the God of Isaac, and the God of Jacob, has appeared to you." 6 Furthermore the Lord said to him, "Now put your hand in your bosom." And he put his hand in his bosom, and when he took it out, behold, his hand was leprous, like snow. 7 And He said, "Put your hand in your bosom again." So he put his hand in his bosom again, and drew it out of his bosom, and behold, it was restored like his other flesh. 8 "Then it will be, if they do not believe you, nor heed the message of the first sign, that they may believe the message of the latter sign. 9 And it shall be, if they do not believe even these two signs, or listen to your voice, that you shall take water from the river and pour it on the dry land. And the water which you take from the river will become blood on the dry land."
Matthew Henry's Commentary on Exodus 4:4-9
Commentary on Exodus 4:1-9
(Read Exodus 4:1-9)
Moses objects, that the people would not take his word, unless he showed them some sign. God gives him power to work miracles. But those who are now employed to deliver God's messages to men, need not the power to work miracles: their character and their doctrines are to be tried by that word of God to which they appeal. These miracles especially referred to the miracles of the Lord Jesus Christ. It belonged to Him only, to cast the power of the devil out of the soul, and to heal the soul of the leprosy of sin; and so it was for Him first to cast the devil out of the body, and to heal the leprosy of the body.