Exodus 7:14

10 So Moses and Aaron went to Pharaoh and did just as the LORD had commanded. Aaron threw his staff down before Pharaoh and his officials, and it became a serpent.

11 But Pharaoh called the wise men and sorcerers and magicians of Egypt, and they also did the same things by their magic arts.

12 Each one threw down his staff, and it became a serpent. But Aaron’s staff swallowed up the other staffs.

13 Still, Pharaoh’s heart was hardened, and he would not listen to them, just as the LORD had said.

14 Then the LORD said to Moses, “Pharaoh’s heart is unyielding; he refuses to let the people go.

15 Go to Pharaoh in the morning as you see him walking out to the water. Wait on the bank of the Nile to meet him, and take in your hand the staff that was changed into a snake.

16 Then say to him, ‘The LORD, the God of the Hebrews, has sent me to tell you: Let My people go, so that they may worship Me in the wilderness. But you have not listened until now.

17 This is what the LORD says: By this you will know that I am the LORD. Behold, with the staff in my hand I will strike the water of the Nile, and it will turn to blood.

18 The fish in the Nile will die, the river will stink, and the Egyptians will be unable to drink its water.’”

Read all of Exodus 7