Exodus 8:15

8:15 But when Pharaoh saw that there was relief, he hardened his heart and did not listen to them, just as the Lord had predicted.

Exodus 10:1

The Eighth Blow: Locusts

10:1 The Lord said to Moses, “Go to Pharaoh, for I have hardened his heart and the heart of his servants, in order to display these signs of mine before him,

Exodus 10:20

10:20 But the Lord hardened Pharaoh’s heart, and he did not release the Israelites.

Exodus 10:27

10:27 But the Lord hardened Pharaoh’s heart, and he was not willing to release them.

Zechariah 7:12

7:12 Indeed, they made their heart as hard as diamond, so that they could not obey the Torah and the other words the Lord who rules over all had sent by his Spirit through the former prophets. Therefore, the Lord who rules over all had poured out great wrath.