Exodus 4:10-12

10And Moses said to Jehovah, Ah Lord! I am not eloquent, neither heretofore nor since thou hast spoken to thy servant, for I am slow of speech and of a slow tongue.

11And Jehovah said to him, Who gave man a mouth? or who maketh dumb, or deaf, or seeing, or blind? [have] not I, Jehovah?

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