'Hardness' in the Bible

And when he had looked round about on them with anger, being grieved for the hardness of their hearts, he saith unto the man, Stretch forth thine hand. And he stretched it out: and his hand was restored whole as the other.

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?

And Jesus answered and said unto them, For the hardness of your heart he wrote you this precept.

Afterward he appeared unto the eleven as they sat at meat, and upbraided them with their unbelief and hardness of heart, because they believed not them which had seen him after he was risen.