This is an excerpts from Lü Dongbin's The Secret of the Golden Flower, specifically Chapter 13, "Song of Admonition to the World," detailing a Taoist internal alchemy practice called "returning the light." The practice involves cultivating inner energy through breath control and meditation, aiming to achieve enlightenment and immortality. Key concepts include aligning the body's energies ("Kan and Li"), focusing on a specific internal point ("Mysterious Pass"), and achieving a state of emptiness and stillness. The text includes verses summarizing the practice and cautions against distractions, emphasizing diligent practice as crucial to success.