Mark 16:14
The Great Commission
14 Afterward mhe appeared pto the eleven themselves as they were reclining at table, and he rebuked them for their qunbelief and rhardness of heart, because sthey had not believed those who saw him after he had risen.
Mark 3:5
5 And he glooked around at them with anger, grieved at htheir hardness of heart, and said to the man, “Stretch out your hand.” iHe stretched it out, and his hand was restored.
Mark 6:52
52 for fthey did not understand about the loaves, but their hearts gwere hardened.
Hebrews 3:8
8 do not harden your hearts as in the rebellion,
on the day of testing in the wilderness,