Exodus 7:12-14

King James Version

¹² For they cast down every man his rod, and they became serpents: but Aaron's rod swallowed up their rods.

¹³ And he hardened Pharaoh's heart, that he hearkened not unto them; as the Lord had said.

¹⁴ And the Lord said unto Moses, Pharaoh's heart is hardened, he refuseth to let the people go.