Exodus 4:10-12 (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.