Watchman Nee explores the concept of 'flesh' in the Bible, distinguishing between the physical body and the psychological desires that arise from it. He emphasizes that the term 'flesh' encompasses both our physical form and the various lusts associated with our senses, such as the desire for beauty, gratification, and sensory pleasures. Nee highlights the importance of understanding these desires as they can lead us away from spiritual fulfillment. By recognizing the dual nature of flesh, believers can better navigate their spiritual journey and resist temptations. Ultimately, the sermon calls for a deeper awareness of how our physical and psychological desires influence our relationship with God.