'Hardened' in the Bible

For they considered not the miracle of the loaves: for their heart was hardened.

And when Jesus knew it, he saith unto them, Why reason ye, because ye have no bread? perceive ye not yet, neither understand? have ye your heart yet hardened?

He hath blinded their eyes, and hardened their heart; that they should not see with their eyes, nor understand with their heart, and be converted, and I should heal them.

But when divers were hardened, and believed not, but spake evil of that way before the multitude, he departed from them, and separated the disciples, disputing daily in the school of one Tyrannus.

But exhort one another daily, while it is called To day; lest any of you be hardened through the deceitfulness of sin.