Exodus 7:3-13 NRS

3 But I will harden Pharaoh's heart, and I will multiply my signs and wonders in the land of Egypt.
4 When Pharaoh does not listen to you, I will lay my hand upon Egypt and bring my people the Israelites, company by company, out of the land of Egypt by great acts of judgment.
5 The Egyptians shall know that I am the Lord, when I stretch out my hand against Egypt and bring the Israelites out from among them."
6 Moses and Aaron did so; they did just as the Lord commanded them.
7 Moses was eighty years old and Aaron eighty-three when they spoke to Pharaoh.
8 The Lord said to Moses and Aaron,
9 "When Pharaoh says to you, "Perform a wonder,' then you shall say to Aaron, "Take your staff and throw it down before Pharaoh, and it will become a snake.' "
10 So Moses and Aaron went to Pharaoh and did as the Lord had commanded; Aaron threw down his staff before Pharaoh and his officials, and it became a snake.
11 Then Pharaoh summoned the wise men and the sorcerers; and they also, the magicians of Egypt, did the same by their secret arts.
12 Each one threw down his staff, and they became snakes; but Aaron's staff swallowed up theirs.
13 Still Pharaoh's heart was hardened, and he would not listen to them, as the Lord had said.