Exodus 7:14-25 New Revised Standard Version (NRSV)
The First Plague: Water Turned to Blood
14 Then the Lord said to Moses, “Pharaoh’s heart is hardened; he refuses to let the people go. 15 Go to Pharaoh in the morning, as he is going out to the water; stand by at the river bank to meet him, and take in your hand the staff that was turned into a snake. 16 Say to him, ‘The Lord, the God of the Hebrews, sent me to you to say, “Let my people go, so that they may worship me in the wilderness.” But until now you have not listened. 17 Thus says the Lord, “By this you shall know that I am the Lord.” See, with the staff that is in my hand I will strike the water that is in the Nile, and it shall be turned to blood. 18 The fish in the river shall die, the river itself shall stink, and the Egyptians shall be unable to drink water from the Nile.’” 19 The Lord said to Moses, “Say to Aaron, ‘Take your staff and stretch out your hand over the waters of Egypt—over its rivers, its canals, and its ponds, and all its pools of water—so that they may become blood; and there shall be blood throughout the whole land of Egypt, even in vessels of wood and in vessels of stone.’”
20 Moses and Aaron did just as the Lord commanded. In the sight of Pharaoh and of his officials he lifted up the staff and struck the water in the river, and all the water in the river was turned into blood, 21 and the fish in the river died. The river stank so that the Egyptians could not drink its water, and there was blood throughout the whole 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 take even this to heart. 24 And all the Egyptians had to dig along the Nile for water to drink, for they could not drink the water of the river.
25 Seven days passed after the Lord had struck the Nile.