Exodus 7:20-22

New Century Version

²⁰ So Moses and Aaron did just as the Lord had commanded. In front of the king and his officers, Aaron raised his walking stick and struck the water in the Nile River. So all the water in the Nile changed into blood. ²¹ The fish in the Nile died, and the river began to stink, so the Egyptians could not drink water from it. Blood was everywhere in the land of Egypt.

²² Using their tricks, the magicians of Egypt did the same thing. So the king was stubborn and refused to listen to Moses and Aaron, just as the Lord had said.