And the Lord hardened the heart of Pharaoh,.... He having often, and so long hardened his own heart, God gave him up to judicial hardness of heart, to his own corruptions, the temptations of Satan, and the lying magicians about him, to make an ill use of everything that offered to him, and put a wrong construction on all that befell him, so that whatever was said to him, or inflicted on him, made no impression to any purpose:

and he hearkened not unto them; to Moses and Aaron, and to the Lord by them:

as the Lord had spoken to Moses; both that he would harden his heart, and he should not hearken to them; all this was no other than what the Lord had said should be, Exodus 4:21.

And the LORD hardened the heart of Pharaoh, and he hearkened not unto them; as the LORD had spoken unto Moses.

9:12 Now 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 commonly punished with judicial hardness. Let us dread this as the sorest judgment a man can be under on this side hell.

9:8-12 When the Egyptians were not wrought upon by the death of their cattle, God sent a plague that seized their own bodies. If lesser judgments do not work, God will send greater. Sometimes God shows men their sin in their punishment. They had oppressed Israel in the furnaces, and now the ashes of the furnace are made a terror to them. The plague itself was very grievous. The magicians themselves were struck with these boils. Their power was restrained before; but they continued to withstand Moses, and to confirm Pharaoh in his unbelief, till they were forced to give way. Pharaoh continued obstinate. He had hardened his own heart, and now God justly gave him up to his own heart's lusts, permitting Satan to blind and harden him. If men shut their eyes against the light, it is just with God to close their eyes. This is the sorest judgment a man can be under out of hell.