'Hardness' in the Bible

He saith unto them, Moses because of the hardness of your hearts suffered you to put away your wives: but from the beginning it was not so.

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.

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.

But after thy hardness and impenitent heart treasurest up unto thyself wrath against the day of wrath and revelation of the righteous judgment of God;

Thou therefore endure hardness, as a good soldier of Jesus Christ.