What does the Bible say about unbelief after the resurrection?

The scriptures indicate that unbelief, particularly in light of Christ's resurrection, is a grave issue. In Mark 16:14, Jesus chastises His disciples for their hard-heartedness and disbelief after witnessing His resurrection. This serves as a warning to all believers about the perils of indifference towards such a pivotal event. Historically, the hardness of heart led the disciples to miss important truths that could transform their faith. Thus, the call is for believers to actively nurture their faith, ensuring that they do not harden their hearts to the truths of God's word.