Exodus 7:17-21

17Thus says the Lord, “By this you shall know and recognize and acknowledge that I am the Lord: look, with the staff in my hand I will strike the water in the Nile, and it shall be turned to blood.

18The fish in the Nile will die, and the Nile will become foul, and the Egyptians will not be able to drink water from the Nile.” ’ ”

19Then the Lord said to Moses, “Say to Aaron, ‘Take your staff and stretch out your hand over the waters of Egypt, over their rivers, over their streams, over their pools, and over all their reservoirs of water, so that they may become blood; and there shall be blood throughout all the land of Egypt, in containers both of wood and of stone.’ ”

20So Moses and Aaron did as the Lord commanded; Aaron lifted up the staff and struck the waters in the Nile, in the sight of Pharaoh and in the sight of his servants, and all the water that was in the Nile was turned into blood.

21The fish in the Nile died, and the river became foul smelling, and the Egyptians could not drink its water, and there was blood throughout all the land of Egypt.