Hebrews 3:8
harden not your hearts, as in the bitter provocation, in the day of trial in the wilderness,
Matthew 13:15
For the heart of this people has become fat; and with their ears they hear heavily; and their eyes they have closed; lest they should see with their eyes, and hear with their ears, and understand with their heart, and should turn to me, and I should give them health.
Acts 19:9
But as some were hardened, and did not believe, and spoke evil of that way before the multitude, he withdrew from them, and separated the disciples, and discoursed daily in the school of one Tyrannus.
Romans 2:5-6
But, according to your hard and impenitent heart, you treasure up to yourself wrath for a day of wrath, and of the revelation of the righteous judgment of God,
1 Corinthians 10:9
Nor let us tempt the Christ, as some of them also tempted, and were destroyed by serpents.
Hebrews 3:12-13
Take heed, brethren, lest there be in any of you an evil heart of unbelief in apostatizing from the living God.