Exodus 7:19-22

19Then the Lord said to Moses, ‘Say to Aaron, “Take your stick. Lift up your hand over the waters of Egypt. Lift your stick up over their rivers and their streams. Lift it up over their lakes and pools of water. Do that so that all the water becomes blood.” There will be blood in every part of Egypt. There will even be blood in their buckets and bowls.’

20Moses and Aaron obeyed the command of the Lord. Aaron lifted up the stick in front of Pharaoh and his servants. He hit the water in the Nile river with the stick. Then all the water in the river became blood.

21The fish in the river died. The river had such a bad smell that the Egyptians could not drink its water. There was blood in every part of Egypt.

22But the Egyptian magicians used their magic and they did the same thing. So Pharaoh's mind continued to be hard. He still refused to listen to Moses and Aaron. The Lord had said that this would happen, and it did!