Exodus 11:9
And the LORD said unto Moses, Pharaoh shall not hearken unto you; that my wonders may be multiplied in the land of Egypt.
Exodus 7:3-4
And I will harden Pharaoh's heart, and multiply my signs and my wonders in the land of Egypt.
Exodus 3:19
And I am sure that the king of Egypt will not let you go, no, not by a mighty hand.
Exodus 10:1
And the LORD said unto Moses, Go in unto Pharaoh: for I have hardened his heart, and the heart of his servants, that I might show these my signs before him:
Romans 9:16-18
So then it is not of him that wills, nor of him that runs, but of God that shows mercy.