This classic is an important treatise of Taoism in Sui and Tang Dynasties. Scripture is a question and answer between the Yuan God and the immortals such as the Dharma realm, the wonderful star, the naive emperor and the orthodox school. , and promote the teachings and teaching methods. There is an appendix after each paragraph. Its content is quite extensive, involving cause and effect, merit, management discipline, practice order, practice methods, etc. Based on the development of the true meaning of the world, it points out the methods to emphasize metaphysics. The scripture claims that this scripture is the only true law of Taoism. It means that the avenue transcends existence, is naturally empty, has no roots, no roots, no ancestors and no sects. "The person who said this is unobstructed, just like vanity. Nothing, ignorance, ignorance, fruit, holiness, color, mind and phase. That is, all laws are nothing. Why? All laws are asexual, and all laws and Tao are empty after all, empty, empty and there is no difference. Since the Tao is empty, the so-called sentient beings return to their roots, without roots, without roots. All beings can't understand this, but they can't think of Dharma and can't dream in the air. " They make up all kinds of laws and count me and things, so the name life and death cannot be true. "The author has this feeling, so it is proposed that the cultivation of immortals should first break the illusion of thinking, neither stay in existence nor cling to nothingness, and forget existence or even metaphysics at the same time. Therefore, the scripture says, "All ordinary people who are addicted to cigarettes dye everything. Although there is a long illness, it can't stagnate, so it is empty and its stagnation is eliminated. Although there is stagnation, it is still stagnant in the air, often called desire, so it shows that there is nothing. There are two nets in the air, so it is said that forgetting at the same time is the phase of entering the right view. It is also called: "People who are looking at the right view have everything in front of them, whether they have it or not; The second time you were sent into the air, it was empty and clean, but you forgot it at the same time ... If you are a walker, there is nothing, which is called mystery; I sent this Xuan again and found nothing, so I named it Xuan, the Gate of Wan Qi. " This way of forgetting the mystery is the highest state of monasticism. This book had an important influence on the metaphysical philosophy of Taoism in Sui and Tang Dynasties.