Exodus 4:10-17

Then Moses said to the LORD, “Please, Lord, I am not a man of words (eloquent, fluent), neither before nor since You have spoken to Your servant; for I am slow of speech and tongue.” The LORD said to him, “Who has made man’s mouth? Or who makes the mute or the deaf, or the seeing or the blind? Is it not I, the LORD? Now then go, and I, even I, will be with your mouth, and will teach you what you shall say.” But he said, “Please my Lord, send the message [of rescue to Israel] by [someone else,] whomever else You will [choose].” Then the anger of the LORD was kindled and burned against Moses; He said, “Is there not your brother, Aaron the Levite? I know that he speaks fluently. Also, he is coming out to meet you, and when he sees you, he will be overjoyed. You must speak to him and put the words in his mouth; I, even I, will be with your mouth and with his mouth, and I will teach you what you are to do. Moreover, he shall speak for you to the people; he will act as a mouthpiece for you, and you will be as God to him [telling him what I say to you]. You shall take in your hand this staff, with which you shall perform the signs [the miracles which prove I sent you].”