Romans 2:5
but, after your hardness and impenitent heart, you are treasuring up for yourself wrath in the day of wrath and of the revelation of the righteous judgment of God,
Hebrews 3:8-9
harden not your hearts, as in the provocation, in the day of temptation in the wilderness,
Hebrews 3:13
but exhort one another daily, so long as it is called "To-day," lest anyone of you be hardened by the deceitfulness of sin;
Hebrews 3:15-19
while it is said, "To-day, if ye hear His voice, harden not your hearts as in the provocation."
Hebrews 12:25
See that ye refuse not Him Who speaketh; for, if those escaped not, when refusing him who warned them on earth, much more shall not we escape, who turn away from Him Who warneth us from Heaven;
Jude 1:5
Now I wish to put you in remembrance, though ye know all things once for all, that the Lord, having saved the people out of the land of Egypt, afterward destroyed those who believed not.
Acts 19:9
But, when some were hardening themselves and were disbelieving, speaking evil of the Way before the multitude, he, withdrawing from them, separated the disciples; reasoning daily in the school of Tyrannus.