Exodus 4:16 in the King James Version
And he shall be thy spokesman unto the people: and he shall be, even he shall be to thee instead of a mouth, and thou shalt be to him instead of God.
Context
15 You shall speak to him, and put the words in his mouth. I will be with your mouth, and with his mouth, and will teach you what you shall do.
16 He will be your spokesman to the people. It will happen that he will be to you a mouth, and you will be to him as God.
17 You shall take this rod in your hand, with which you shall do the signs.”