Scripture of the Fundamental Aspect 太上妙法本相经

The author is unknown. It was probably compiled in the late Northern and Southern Dynasties or between the Sui and Tang dynasties.

The original work had at least more than twenty volumes. The surviving version in the Daozang consists of only three incomplete volumes, included in the Taiping Section.

In addition, according to the catalog Dunhuang Daojing Mulu Bian (Compilation of Catalogues of Taoist Scriptures from Dunhuang) by Onoda Shunji, there are twelve incomplete Tang Dynasty manuscripts of the Benxiang Jing among the Dunhuang relics. Among them, eight manuscripts—including P2429, S2122, P2389, P2476, P3091, and the copy collected by Zhengsongtang—contain content not found in the Daozang version. Manuscripts such as P2357, S3173, P2396, and P2755 have numerous textual variations from the Daozang version. Furthermore, many lost passages of the Benxiang Jing are preserved in Tang and Song Buddhist and Taoist classics such as Shangqing Dao Lei Shixiang (Classified Matters of the Shangqing Dao) and Yaoxiu Keyi Jielü Chao (Excerpts of Essential Cultivation Rituals and Precepts). Falsely attributed to debates between the Primordial Lord, "the Debater," and non-Taoist adherents, this scripture explains the doctrines of Taoism as well as the essentials of fasts and magical arts. Its content is quite diverse, covering the origin of the universe, the karmic causes and retributions of all sentient beings, governing a state and cultivating oneself, and practicing the Dao to seek immortality. Its main tenets are based on the Daode Jing (Classic of the Way and Virtue) and influenced by the Lingbao Jing (Numinous Treasure Scriptures). It states: "The Dao is the father of all things; emptiness is the mother of all things." Those who study the Dao should uphold the Dao and embody virtue, perform actions that are non-action, abide in thoughts that are non-thought, and dwell in attachments that are non-attachment. It also refutes non-Taoist schools and argues for the existence of karmic causes from past lives, stating: "All sentient beings have their own karmic affinities; merits and transgressions accumulated in past lives are endured in this life, and deeds done in this life will be endured in future lives." Additionally, it emphasizes the importance of respecting teachers while studying the Dao and observing fasts and precepts, asserting that both cultivating oneself and governing a state should be based on non-action and non-desire. The mention in Dunhuang manuscripts of "entrusting to Mao Jin (the Liu clan), and Muzi Gongkou (the Li clan) shall flourish" indicates that this scripture was influenced by the Dongyuan Shenzhou Jing (Scripture of the Divine Mantras of the Cavernous Abyss).