Exodus 4:9-11

Complete Jewish Bible

⁹ But if they aren’t persuaded even by both these signs and still won’t listen to what you say, then take some water from the river, and pour it on the ground. The water you take from the river will turn into blood on the dry land.”

¹⁰ Moshe said to Adonai, “Oh, Adonai, I’m a terrible speaker. I always have been, and I’m no better now, even after you’ve spoken to your servant! My words come slowly, my tongue moves slowly.” ¹¹ Adonai answered him, “Who gives a person a mouth? Who makes a person dumb or deaf, keen-sighted or blind? Isn’t it I, Adonai?