Hebrews 3:8

harden not your hearts, as in that bitter provocation, at the day of the temptation in the wilderness;

Matthew 13:15

for the heart of this people is waxed gross, and with their ears they have heard heavily, and their eyes they have closed; lest at any time they should see with the eves, and hear with the ears, and understand with the heart, and be converted, and I should heal them.

Acts 19:9

And when some were hardened, and infidel, speaking evil of the way before the people, he withdrew from them, and separated the disciples, discoursing daily in the school of one Tyrannus.

Romans 2:5-6

But after thy obdurate and impenitent heart treasurest up for thyself wrath at the day of wrath and revelation of the righteous judgment of God,

1 Corinthians 10:9

Neither let us tempt Christ, as some of them also tempted, and were destroyed by serpents.

Hebrews 3:12-13

Take heed, brethren, that there be not in any one of you a wicked heart of infidelity, [evident] in departure from the living God:

Treasury of Scripture Knowledge

Summary

Harden not your hearts, as in the provocation, in the day of temptation in the wilderness:

General references

Bible References

Harden

Hebrews 3:12
Take heed, brethren, that there be not in any one of you a wicked heart of infidelity, [evident] in departure from the living God:
Matthew 13:15
for the heart of this people is waxed gross, and with their ears they have heard heavily, and their eyes they have closed; lest at any time they should see with the eves, and hear with the ears, and understand with the heart, and be converted, and I should heal them.
Acts 19:9
And when some were hardened, and infidel, speaking evil of the way before the people, he withdrew from them, and separated the disciples, discoursing daily in the school of one Tyrannus.
Romans 2:5
But after thy obdurate and impenitent heart treasurest up for thyself wrath at the day of wrath and revelation of the righteous judgment of God,

Of

1 Corinthians 10:9
Neither let us tempt Christ, as some of them also tempted, and were destroyed by serpents.

General references

Luke 8:6
And other seed fell on a rock, and vegetating, withered because it had no moisture.