'Hardness' in the Bible

Who [is] like the sage? Who knows [the] interpretation of a thing? A man's wisdom makes his face shine, and the hardness of his face is changed.

{And just as} you saw the feet and the toes, {partly potter's clay} and {partly iron}, it will be a divided kingdom; and {some hardness} of the iron will be [in it], {just as} you have seen the iron mixed with the wet clay.

He said to them, "Moses, with reference to your hardness of heart, permitted you to divorce your wives, but from the beginning it was not like this.

And looking around at them with anger, grieved at the hardness of their hearts, he said to the man, "Stretch out your hand." And he stretched [it] out, and his hand was restored.

But Jesus said to them, "He wrote this commandment for you because of your hardness of heart.

And later, [while] they were reclining at table, he appeared to the eleven. And he reprimanded their unbelief and hardness of heart, because they did not believe those who had seen him [after he] had been raised.

being darkened in understanding, alienated from the life of God, because of the ignorance [that] is in them, because of the hardness of their heart,