Mark 6:52
for they had not understood about the loaves, but their hearts were hardened.
Mark 3:5
And when he had looked around at them with anger, being grieved at the hardening of their hearts, he said to the man, "Stretch out your hand." He stretched it out, and his hand was restored.
Mark 8:17-21
He, perceiving it, said to them, "Why do you reason that it's because you have no bread? Do you not perceive yet, neither understand? Are your hearts hardened?
Isaiah 63:17
O LORD, why do you make us to stray from your ways, and harden our heart from your fear? Return for your servants' sake, the tribes of your inheritance.
Matthew 16:9-11
Do you still not understand? Do you not remember the five loaves for the five thousand, and how many baskets you took up?
Mark 7:18
He said to them, "Are you thus without understanding also? Do you not perceive that whatever goes into the man from outside cannot defile him,
Mark 16:14
Afterward he was revealed to the Eleven themselves as they sat at the table, and he rebuked them for their unbelief and hardness of heart, because they did not believe those who had seen him after he had risen.
Luke 24:25
Then he said to them, "O foolish ones, and slow of heart to believe in all that the prophets have spoken.
Romans 11:7
What then? That which Israel seeks for, that he did not obtain, but the chosen ones obtained it, and the rest were hardened.