Exodus 9:12
“And the Lord hardened the heart of Pharaoh, and he hearkened not unto them; as the Lord had spoken unto Moses.”
And they took ashes of the furnace, and stood before Pharaoh; and Moses sprinkled it up toward heaven; and it became a boil breaking forth with blains upon man, and upon beast.
And the magicians could not stand before Moses because of the boils; for the boil was upon the magicians, and upon all the Egyptians.
And the Lord hardened the heart of Pharaoh, and he hearkened not unto them; as the Lord had spoken unto Moses.
And the Lord said unto Moses, Rise up early in the morning, and stand before Pharaoh, and say unto him, Thus saith the Lord God of the Hebrews, Let my people go, that they may serve me.
For I will at this time send all my plagues upon thine heart, and upon thy servants, and upon thy people; that thou mayest know that there is none like me in all the earth.
Counter-Arguments
The strongest case that this verse does not belong in this theme.

Related Verses
“And the heart of Pharaoh was hardened, neither would he let the children of Israel go; as the Lord had spoken by Moses.”
“And he hardened Pharaoh’s heart, that he hearkened not unto them; as the Lord had said.”
“But the Lord hardened Pharaoh’s heart, so that he would not let the children of Israel go.”
“Then the magicians said unto Pharaoh, This is the finger of God: and Pharaoh’s heart was hardened, and he hearkened not unto them; as the Lord had said.”
“But when Pharaoh saw that there was respite, he hardened his heart, and hearkened not unto them; as the Lord had said.”