Exodus 9:12

9:12 But the Lord hardened Pharaoh’s heart, and he did not listen to them, just as the Lord had predicted to Moses.

Exodus 9:17

9:17 You are still exalting yourself against my people by not releasing them.

Exodus 9:34-35

9:34 When Pharaoh saw that the rain and hail and thunder ceased, he sinned again: both he and his servants hardened their hearts. 9:35 So Pharaoh’s heart remained hard, and he did not release the Israelites, as the Lord had predicted through Moses.