20 But the LORD hardened Pharaoh's heart, and he did not let the children of Israel go.
Exodus 10:20 Cross References - JPS_ASV_Byz
Exodus 4:21
21 And the LORD said unto Moses: 'When thou goest back into Egypt, see that thou do before Pharaoh all the wonders which I have put in thy hand; but I will harden his heart, and he will not let the people go.
Exodus 7:13-14
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.
Exodus 11:10
10 And Moses and Aaron did all these wonders before Pharaoh; and the LORD hardened Pharaoh's heart, and he did not let the children of Israel go out of his land.
Deuteronomy 2:30
30 But Sihon king of Heshbon would not let us pass by him; for the LORD thy God hardened his spirit, and made his heart obstinate, that He might deliver him into thy hand, as appeareth this day.
Isaiah 6:9-10
9 And He said: 'Go, and tell this people: hear ye indeed, but understand not; and see ye indeed, but perceive not.
10 Make the heart of this people fat, and make their ears heavy, and shut their eyes; lest they, seeing with their eyes, and hearing with their ears, and understanding with their heart, return, and be healed.'
John 12:39-40
Romans 9:18
18 So then he hath mercy on whom he will, and whom he will be hardeneth.