Exodus 9:34-35

Young's Literal Translation

³⁴ and Pharaoh seeth that the rain hath ceased, and the hail and the voices, and he continueth to sin, and hardeneth his heart, he and his servants;

³⁵ and the heart of Pharaoh is strong, and he hath not sent the sons of Israel away, as Jehovah hath spoken by the hand of Moses.