'Hardened' in the Bible

because they did not understand concerning the loaves, but their hearts were hardened.

And knowing [this], he said to them, "Why are you discussing that you have no bread? Do you not yet perceive or understand? Have your hearts been hardened?

"He has blinded their eyes and hardened their hearts, lest they see with [their] eyes and understand with [their] hearts and turn, and I heal them."

But when some became hardened and were disobedient, reviling the Way before the congregation, he departed from them [and] took away the disciples, leading discussions every day in the lecture hall of Tyrannus.

What then? What Israel was searching for, this it did not obtain. But the elect obtained [it], and the rest were hardened,

But their minds were hardened. For until this very day, the same veil remains upon the reading of the old covenant, not being uncovered, because it is done away with in Christ.

But encourage one another {day by day}, as long as it is called "today," so that {none of you become hardened} by the deception of sin.