Exodus 7:8-13

The LORD said to Moses and Aaron, “Moses, when the king asks you to do a miracle, tell Aaron to throw his walking stick down in front of the king, and it will become a snake.” So Moses and Aaron went to the king as the LORD had commanded. Aaron threw his walking stick down in front of the king and his officers, and it became a snake. So the king called in his wise men and his magicians, and with their tricks the Egyptian magicians were able to do the same thing. They threw their walking sticks on the ground, and their sticks became snakes. But Aaron’s stick swallowed theirs. Still the king was stubborn and refused to listen to Moses and Aaron, just as the LORD had said.