Exodus 7:12-14

Young's Literal Translation

¹² and they cast down each his rod, and they become monsters, and the rod of Aaron swalloweth their rods;

¹³ and the heart of Pharaoh is strong, and he hath not hearkened unto them, as Jehovah hath spoken.

¹⁴ And Jehovah saith unto Moses, `The heart of Pharaoh hath been hard, he hath refused to send the people away;