"When Pharaoh says to you, 'Prove yourselves by working a miracle,' then you shall say to Aaron, 'Take your rod and cast it down before Pharaoh, that it may become a serpent.'"
So Moses and Aaron went to Pharaoh and did as the LORD commanded; Aaron cast down his rod before Pharaoh and his servants, and it became a serpent.
Then Pharaoh summoned the wise men and the sorcerers; and they also, the magicians of Egypt, did the same by their secret arts.
For every man cast down his rod, and they became serpents. But Aaron's rod swallowed up their rods.
Still Pharaoh's heart was hardened, and he would not listen to them; as the LORD had said.
Then the LORD said to Moses, "Pharaoh's heart is hardened, he refuses to let the people go.
Go to Pharaoh in the morning, as he is going out to the water; wait for him by the river's brink, and take in your hand the rod which was turned into a serpent.
And you shall say to him, 'The LORD, the God of the Hebrews, sent me to you, saying, "Let my people go, that they may serve me in the wilderness; and behold, you have not yet obeyed."
Thus says the LORD, "By this you shall know that I am the LORD: behold, I will strike the water that is in the Nile with the rod that is in my hand, and it shall be turned to blood,
and the fish in the Nile shall die, and the Nile shall become foul, and the Egyptians will loathe to drink water from the Nile."'"
And the LORD said to Moses, "Say to Aaron, 'Take your rod and stretch out your hand over the waters of Egypt, over their rivers, their canals, and their ponds, and all their pools of water, that they may become blood; and there shall be blood throughout all the land of Egypt, both in vessels of wood and in vessels of stone.'"
Revised Standard Version of the Bible, copyright 1952 [2nd edition, 1971] by the Division of Christian Education of the National Council of the Churches of Christ in the United States of America. Used by permission. All rights reserved. (Revised Standard Version - Holy Bible)