4 But the Lord said to Moses, "Put out your hand and catch it by the tail"--so he put out his hand and caught it, and it became a staff in his hand-- 5 "that they may believe that the Lord, the God of their fathers, the God of Abraham, the God of Isaac, and the God of Jacob, has appeared to you." 6 Again, the Lord said to him, "Put your hand inside your cloak."[1] And he put his hand inside his cloak, and when he took it out, behold, his hand was leprous[2] like snow. 7 Then God said, "Put your hand back inside your cloak." So he put his hand back inside his cloak, and when he took it out, behold, it was restored like the rest of his flesh. 8 "If they will not believe you," God said, "or listen to the first sign, they may believe the latter sign. 9 If they will not believe even these two signs or listen to your voice, you shall take some water from the Nile and pour it on the dry ground, and the water that you shall take from the Nile will become blood on the dry ground."
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.