Mark 4:12
that seeing they may see, and not perceive, and hearing they may hear, and not understand, lest at any time they should turn, and be forgiven.
Mark 8:17-21
And Jesus knowing it, said to them, Why do you reason because you have no bread? Do you not yet perceive nor understand? Is your heart hardened?
Ephesians 2:11
Wherefore, remember that you were formerly gentiles by birth, called uncircumcision by that called circumcision made in the flesh by the hand,
2 Thessalonians 2:10-12
and with every unrighteous deceit among those who are destroyed, because they received not the love of the truth that they might be saved.