4 And Jehovah said unto Moses, Put forth thy hand, and take it by the tail: (and he put forth his hand, and laid hold of it, and it became a rod in his hand:) 5 That they may believe that Jehovah, the God of their fathers, the God of Abraham, the God of Isaac, and the God of Jacob, hath appeared unto thee. 6 And Jehovah said furthermore unto him, Put now thy hand into thy bosom. And he put his hand into his bosom: and when he took it out, behold, his hand was leprous, as [white as] snow. 7 And he said, Put thy hand into thy bosom again. (And he put his hand into his bosom again; and when he took it out of his bosom, behold, it was turned again as his [other] flesh.) 8 And it shall come to pass, if they will not believe thee, neither hearken to the voice of the first sign, that they will believe the voice of the latter sign. 9 And it shall come to pass, if they will not believe even these two signs, neither hearken unto thy voice, that thou shalt take of the water of the river, and pour it upon the dry land: and the water which thou takest out of the river shall become blood upon 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.