The sermon discusses the concept of unclean spirits and their influence, emphasizing that simply removing negative influences is not enough; one must also replace them with positive actions and spiritual growth. It highlights biblical teachings that stress the importance of living a godly life and warns against the dangers of being spiritually unprepared, as unclean spirits may return with greater force if the house (body) is left empty. The message concludes with the assurance that individuals can overcome evil by following the teachings of Christ and engaging in positive actions.