Exodus 4:8-10

Amplified Bible, Classic Edition

⁸ [Then God said] If they will not believe you or heed the voice or the testimony of the first sign, they may believe the voice or the witness of the second sign.

⁹ But if they will also not believe these two signs or heed your voice, you shall take some water of the river [Nile] and pour it upon the dry land; and the water which you take out of the river [Nile] shall become blood on the dry land.

¹⁰ And Moses said to the Lord, O Lord, I am not eloquent or a man of words, neither before nor since You have spoken to Your servant; for I am slow of speech and have a heavy and awkward tongue.