Exodus 4:10-14 (KJV)
10 And 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.
11 And 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?
12 Now therefore go, and I will be with thy mouth, and teach thee what thou shalt say.
13 And he said, O my Lord, send, I pray thee, by the hand of him whom thou wilt send.
14 And 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.