“And I will harden Pharaoh’s heart, and he will pursue them.
But I will gain glory for myself through Pharaoh and all his army,
and the Egyptians will know that I am the Lord.”
Exodus 14, 4

But when Pharaoh saw that there was relief,
he hardened his heart and did not heed them,
as the Lord had said.
Exodus 8:15

But Pharaoh hardened his heart at this time also;
neither would he let the people go.
Exodus 8:32

And when Pharaoh saw that the rain, the hail, and the thunder had ceased,
he sinned yet more; and he hardened his heart, he and his servants.
Exodus 9:34

14 What shall we say then? Is there injustice on God’s part? By no means! 15 For he says
to Moses, “I will have mercy on whom I have mercy, and I will have compassion on
whom I have compassion.” 16 So it depends not upon man’s will or exertion, but upon
God’s mercy. 17 For the scripture says to Pharaoh, “I have raised you up for the very
purpose of showing my power in you, so that my name may be proclaimed in all the
earth.” 18 So then he has mercy upon whomever he wills, and he hardens the heart of
whomever he wills. 19 You will say to me then, “Why does he still find fault? For who can
resist his will?” 20 But who are you, a man, to answer back to God? Will what is molded
say to its molder, “Why have you made me thus?” 21 Has the potter no right over the
clay, to make out of the same lump one vessel for beauty and another for menial use? 22
What if God, desiring to show his wrath and to make known his power, has endured
with much patience the vessels of wrath made for destruction, 23 in order to make
known the riches of his glory for the vessels of mercy, which he has prepared beforehand
for glory,
Romans 9, 14-23