Exodus 4:10-12

10But Moses said to Adonai, “Adonai, I am not a man of words—not yesterday, nor the day before, nor since You have spoken to Your servant—because I have a slow mouth and a heavy tongue.”

11So Adonai said to him, “Who made man’s mouth? Or who makes a man mute or deaf, seeing or blind? Is it not I, Adonai?

12Now go! I will be with your mouth and teach you what to say.”