David Wilkerson addresses the peril of a hardened heart, emphasizing that repeated rejection of God's warnings leads to an incurable state. He explains that hardness of heart is characterized by a refusal to obey God's Word and an immunity to the Holy Spirit's convictions. Wilkerson contrasts this with the transformative power of the gospel, illustrating how even the hardest of hearts can be softened when exposed to the truth. He warns that those who frequently hear reproof yet remain unresponsive are at the greatest risk of spiritual destruction. Ultimately, he highlights the importance of heeding God's messages to avoid the tragic fate of being beyond remedy.