Exodus 4:10-16 KJV

8And 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.

9And it shall come to pass, if they will not believe also 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.

10And Moses said unto the LORD, O my LORD, I am not eloquent, neither heretofore, nor since thou hast spoken unto thy servant: but I am slow of speech, and of a slow tongue.

11And the LORD said unto him, Who hath made man’s mouth? or who maketh the dumb, or deaf, or the seeing, or the blind? have not I the LORD?

12Now therefore go, and I will be with thy mouth, and teach thee what thou shalt say.

13And he said, O my LORD, send, I pray thee, by the hand of him whom thou wilt send.

14And the anger of the LORD was kindled against Moses, and he said, Is not Aaron the Levite thy brother? I know that he can speak well. And also, behold, he cometh forth to meet thee: and when he seeth thee, he will be glad in his heart.

15And thou shalt speak unto him, and put words in his mouth: and I will be with thy mouth, and with his mouth, and will teach you what ye shall do.

16And he shall be thy spokesman unto the people: and he shall be, even he shall be to thee instead of a mouth, and thou shalt be to him instead of God.

17And thou shalt take this rod in thine hand, wherewith thou shalt do signs.

18And Moses went and returned to Jethro his father in law, and said unto him, Let me go, I pray thee, and return unto my brethren which are in Egypt, and see whether they be yet alive. And Jethro said to Moses, Go in peace.