41 But Moses protested again, "What if they won't believe me or listen to me? What if they say, 'The Lord never appeared to you'?" 2 Then the Lord asked him, "What is that in your hand?" "A shepherd's staff," Moses replied. 3 "Throw it down on the ground," the Lord told him. So Moses threw down the staff, and it turned into a snake! Moses jumped back. 4 Then the Lord told him, "Reach out and grab its tail." So Moses reached out and grabbed it, and it turned back into a shepherd's staff in his hand. 5 "Perform this sign," the Lord told him. "Then they will believe that the Lord, the God of their ancestors-the God of Abraham, the God of Isaac, and the God of Jacob-really has appeared to you." 6 Then the Lord said to Moses, "Now put your hand inside your cloak." So Moses put his hand inside his cloak, and when he took it out again, his hand was white as snow with a severe skin disease. 7 "Now put your hand back into your cloak," the Lord said. So Moses put his hand back in, and when he took it out again, it was as healthy as the rest of his body. 8 The Lord said to Moses, "If they do not believe you and are not convinced by the first miraculous sign, they will be convinced by the second sign.
Matthew Henry's Commentary on Exodus 4:1-8
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.