'Hardness' in the Bible

He said to them, “Because your hearts were hard and stubborn Moses permitted you to divorce your wives; but from the beginning it has not been this way.

Jesus, aware of this [discussion], said to them, “Why are you discussing [the fact] that you have no bread? Do you still not see or understand? Are your hearts hardened?

But Jesus said to them, “Because of your hardness of hearts [your callousness and insensitivity toward your wives and the provision of God] he wrote you this precept.

Later, Jesus appeared to the eleven [disciples] themselves as they were reclining at the table; and He called them to account for their unbelief and hardness of heart, because they had not believed those who had seen Him after He had risen [from death].

for their [moral] understanding is darkened and their reasoning is clouded; [they are] alienated and self-banished from the life of God [with no share in it; this is] because of the [willful] ignorance and spiritual blindness that is [deep-seated] within them, because of the hardness and insensitivity of their heart.