Exodus 4:9-11

Young's Literal Translation

⁹ `And it hath come to pass, if they do not give credence even to these two signs, nor hearken to thy voice, that thou hast taken of the waters of the River, and hast poured on the dry land, and the waters which thou takest from the River have been, yea, they have become -- blood on the dry land.'

¹⁰ And Moses saith unto Jehovah, `O, my Lord, I [am] not a man of words, either yesterday, or before, or since Thy speaking unto Thy servant, for I [am] slow of mouth, and slow of tongue.'

¹¹ And Jehovah saith unto him, `Who appointed a mouth for man? or who appointeth the dumb, or deaf, or open, or blind? is it not I, Jehovah?