Exodus 7:8-13
7:8 The Lord said to Moses and Aaron,
7:9 “When Pharaoh says to you, ‘Do a miracle,’ and you say to Aaron, ‘Take your staff and throw it down before Pharaoh,’ it will become a snake.”
7:10 When Moses and Aaron went to Pharaoh, they did so, just as the Lord had commanded them – Aaron threw down his staff before Pharaoh and his servants and it became a snake.
7:11 Then Pharaoh also summoned wise men and sorcerers, and the magicians of Egypt by their secret arts did the same thing.
7:12 Each man threw down his staff, and the staffs became snakes. But Aaron’s staff swallowed up their staffs.
7:13 Yet Pharaoh’s heart became hard, and he did not listen to them, just as the Lord had predicted.