And the Lord hardened Pharaoh's heart Before he had hardened his own heart, and resisted the grace of God; and now God justly gave him up to his own heart's lusts, to strong delusions, permitting Satan to blind and harden him. Wilful hardness is generally punished with judicial hardness. Let us dread this as the sorest judgment a man can be under on this side hell.
Related Commentaries of Exodus 9:12
Exodus 9:12
12 And the LORD hardened the heart of Pharaoh, and he hearkened not unto them; as the LORD had spoken unto Moses.