'Hardness' in the Bible

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].