Hebrews 3:8
Continue not to harden your hearts as in the Provocation, On the day of temptation in the wilderness,
Matthew 13:15
For the heart of his people is made fat, Their ears are dull of hearing; Their eyes, too, have they closed, Lest some day their eyes should perceive, And their ears should hear, And their heart should understand and turn, And I should heal them.
Acts 19:9
But when some grew hardened and disobedient, and spoke evil of the Way before the crowd, he left them, withdrew the disciples, and continued to hold discussions daily in the lecture-hall of Tyrannus.
Romans 2:5-6
In your hardness and impenitence of heart you are treasuring up for yourself wrath on the Day of Wrath, when the righteous judgment of God is revealed.
1 Corinthians 10:9
Neither must we presume upon the patience of our Lord, as some of them presumed, and were destroyed by the serpents;
Hebrews 3:12-13
See to it, brothers, that there shall never be in any one of you an evil and unbelieving heart, manifesting itself in apostasy from the living God.