Hebrews 3:8

Continue not to harden your hearts as in the Provocation, On the day of temptation in the wilderness,

Hebrews 3:15

In the words of Scripture, Today, if you hear his voice, Do not continue to harden your hearts as at the Provocation.

Revelation 16:9

And men were scorched with the terrible heat; and they blasphemed the name of the God who had the power over these plagues; yet they repented not, to give him glory.

Treasury of Scripture Knowledge

Summary

But when Pharaoh saw that there was respite, he hardened his heart, and hearkened not unto them; as the LORD had said.

Bible References

He hardened

Hebrews 3:8
Continue not to harden your hearts as in the Provocation, On the day of temptation in the wilderness,
Revelation 16:9
And men were scorched with the terrible heat; and they blasphemed the name of the God who had the power over these plagues; yet they repented not, to give him glory.