for they did not understand about the loaves, but their hearts were hardened.

And Jesus, aware of this, said to them, “Why are you discussing the fact that you have no bread? Do you not yet perceive or understand? Are your hearts hardened?

“He has blinded their eyes and hardened their heart, lest they see with their eyes, and understand with their heart, and turn, and I would heal them.”

So then he has mercy on whomever he wills, and he hardens whomever he wills.

What then? Israel failed to obtain what it was seeking. The elect obtained it, but the rest were hardened,

The Mystery of Israel's Salvation

Lest you be wise in your own sight, I do not want you to be unaware of this mystery, brothers: a partial hardening has come upon Israel, until the fullness of the Gentiles has come in.

But their minds were hardened. For to this day, when they read the old covenant, that same veil remains unlifted, because only through Christ is it taken away.

do not harden your hearts as in the rebellion, on the day of testing in the wilderness,

But exhort one another every day, as long as it is called “today,” that none of you may be hardened by the deceitfulness of sin.

As it is said, “Today, if you hear his voice, do not harden your hearts as in the rebellion.”

again he appoints a certain day, “Today,” saying through David so long afterward, in the words already quoted, “Today, if you hear his voice, do not harden your hearts.”