Exodus 7:22-25

22But the magicians of Egypt did the same thing by their occult practices. So Pharaoh’s heart was hard, and he would not listen to them, as the Lord had said.

23Pharaoh turned around, went into his palace, and didn’t take even this to heart.

24All the Egyptians dug around the Nile for water to drink because they could not drink the water from the river.

25Seven days passed after the Lord struck the Nile.