NT-GOSPEL.filter - kjv harden:

kjv@Mark:6:52 @ For they considered not the miracle of the loaves: for their heart was hardened.

kjv@Mark:8:17 @ 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?

kjv@John:12:40 @ 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.