Exodus 7:3-13 GW

3 But I will make Pharaoh stubborn. Even though I will do many miraculous signs and amazing things in Egypt,
4 Pharaoh will not listen to you. Then I will use my power to punish Egypt severely, and I will bring my people, the Israelites, out of Egypt in organized family groups.
5 The Egyptians will know that I am the LORD when I use my power against Egypt and bring the Israelites out of there."
6 Moses and Aaron did as the LORD had commanded them.
7 Moses was 80 years old and Aaron was 83 when they talked to Pharaoh.
8 The LORD said to Moses and Aaron,
9 "When Pharaoh says to you, 'Give me a sign to prove that God has sent you,' tell Aaron, 'Take your shepherd's staff and throw it down in front of Pharaoh,' and it will become a large snake."
10 Moses and Aaron went to Pharaoh and did as the LORD had commanded. Aaron threw his staff down in front of Pharaoh and his officials, and it became a large snake.
11 Then Pharaoh sent for his wise men and sorcerers. These Egyptian magicians did the same thing using their magic spells.
12 Each of them threw his staff down, and they all became large snakes. But Aaron's staff swallowed theirs.
13 Yet, Pharaoh continued to be stubborn and would not listen to them, as the LORD had predicted.