Exodus 7:3-12

3But I will harden Pharaoh's heart, and though I multiply my signs and wonders in the land of Egypt,

4Pharaoh will not listen to you. Then I will lay my hand on Egypt and bring my hosts, my people the children of Israel, out of the land of Egypt by great acts of judgment.

5The Egyptians shall know that I am the Lord, when I stretch out my hand against Egypt and bring out the people of Israel from among them."

6Moses and Aaron did so; they did just as the Lord commanded them.

7Now Moses was eighty years old, and Aaron eighty-three years old, when they spoke to Pharaoh.

8Then the Lord said to Moses and Aaron,

9"When Pharaoh says to you, 'Prove yourselves by working a miracle,' then you shall say to Aaron, 'Take your staff and cast it down before Pharaoh, that it may become a serpent.'"

10So Moses and Aaron went to Pharaoh and did just as the Lord commanded. Aaron cast down his staff before Pharaoh and his servants, and it became a serpent.

11Then Pharaoh summoned the wise men and the sorcerers, and they, the magicians of Egypt, also did the same by their secret arts.

12For each man cast down his staff, and they became serpents. But Aaron's staff swallowed up their staffs.