Exodus 7:21-23

Revised Standard Version

²¹ And the fish in the Nile died; and the Nile became foul, so that the Egyptians could not drink water from the Nile; and there was blood throughout all the land of Egypt. ²² But the magicians of Egypt did the same by their secret arts; so Pharaoh’s heart remained hardened, and he would not listen to them; as the Lord had said. ²³ Pharaoh turned and went into his house, and he did not lay even this to heart.