The sermon examines the destructive fruits of unbelief, specifically highlighting how an evil and departing heart leads to worldly-mindedness. It contrasts walking by sight with walking by faith, warning believers against the deceptive allure of material security and self-obsession. Using the parable of the rich fool from Luke 12, the message illustrates that life does not consist in the abundance of possessions but in trusting God's provision. The preacher urges Christians to set their affection on things above rather than on earthly treasures, emphasizing that only those who do God's will abide forever. Ultimately, the central call is to maintain a heart of belief and humility, resisting the world's pull by focusing on eternal rewards.