Exodus 4:10-16

And Moses said to the Lord, O Lord, I am not eloquent or a man of words, neither before nor since You have spoken to Your servant; for I am slow of speech and have a heavy and awkward tongue. And the Lord said to him, Who has made man's mouth? Or who makes the dumb, or the deaf, or the seeing, or the blind? Is it not I, the Lord? Now therefore go, and I will be with your mouth and will teach you what you shall say. And he said, Oh, my Lord, I pray You, send by the hand of [some other] whom You will [send]. Then the anger of the Lord blazed against Moses; He said, Is there not Aaron your brother, the Levite? I know he can speak well. 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; and I will be with your mouth and with his mouth and will teach you what you shall do. He shall speak for you to the people, acting as a mouthpiece for you, and you shall be as God to him.