Unbelief: Proceeds From: Hardness of Heart
Source: TTT
Mark 16:14
Later, as they were eating, Jesus appeared to the Eleven and rebuked them for their unbelief and hardness of heart, because they did not believe those who had seen Him after He had risen.
Acts 19:9
But when some of them stubbornly refused to believe and publicly maligned the Way, Paul took his disciples and left the synagogue to conduct daily discussions in the lecture hall of Tyrannus.