Yuanshi Tianzun said the Mysterious Sutra, the title of a Taoist book. The year and author of the book are unknown. The text mainly describes the method of contemplating and being convinced and how to preserve the Trinity (God) on time. The so-called "Xuanwei" refers to the inner practice of tranquility and reaching a mysterious and advanced state. It is believed that one can become an immortal through long-term practice. Its content is basically the same as "The Oral Formula for the Five Dou Sanyuan True Sutra of the Emperor Jinque" and "The Oral Formula for Keeping the Five Dou True One Sutra" compiled in the 49th volume of "Yunji Qizhuan", and can be used for mutual reference. Included in the 31st volume of "Tao Zang".
