Exodus 14:8

14:8 But the Lord hardened the heart of Pharaoh king of Egypt, and he chased after the Israelites. Now the Israelites were going out defiantly.

Exodus 14:17

14:17 And as for me, I am going to harden the hearts of the Egyptians so that they will come after them, that I may be honored because of Pharaoh and his army and his chariots and his horsemen.

Exodus 4:21-31

4:21 The Lord said to Moses, “When you go back to Egypt, see that you do before Pharaoh all the wonders I have put under your control. But I will harden his heart and he will not let the people go. 4:22 You must say to Pharaoh, ‘Thus says the Lord, “Israel is my son, my firstborn, 4:23 and I said to you, ‘Let my son go that he may serve me,’ but since you have refused to let him go, I will surely kill your son, your firstborn!”’”

4:24 Now on the way, at a place where they stopped for the night, the Lord met Moses and sought to kill him. 4:25 But Zipporah took a flint knife, cut off the foreskin of her son and touched it to Moses’ feet, and said, “Surely you are a bridegroom of blood to me.” 4:26 So the Lord let him alone. (At that time she said, “A bridegroom of blood,” referring to the circumcision.)

4:27 The Lord said to Aaron, “Go to the wilderness to meet Moses. So he went and met him at the mountain of God and greeted him with a kiss. 4:28 Moses told Aaron all the words of the Lord who had sent him and all the signs that he had commanded him. 4:29 Then Moses and Aaron went and brought together all the Israelite elders. 4:30 Aaron spoke all the words that the Lord had spoken to Moses and did the signs in the sight of the people, 4:31 and the people believed. When they heard that the Lord had attended to the Israelites and that he had seen their affliction, they bowed down close to the ground.

Exodus 7:3

7:3 But I will harden Pharaoh’s heart, and although I will multiply my signs and my wonders in the land of Egypt,

Exodus 7:13-14

7:13 Yet Pharaoh’s heart became hard, and he did not listen to them, just as the Lord had predicted.

The First Blow: Water to Blood

7:14 The Lord said to Moses, “Pharaoh’s heart is hard; he refuses to release the people.

Romans 11:8

11:8 as it is written,

“God gave them a spirit of stupor,

eyes that would not see and ears that would not hear,

to this very day.”