三清为道教最高尊神，分别是玉清元始天尊、上清灵宝天尊、太清道德天尊。是道家哲学“三一”学说的象征。《道德经》第四十二章曰：“道生一，一生二，二生三，三生万物，万物负阴而抱阳，冲气以为和。”由无名大道化生混沌元气，由元气化生阴阳二气，阴阳之相合，生天下万物。第十四章又说“视之不见名曰夷，听之不闻名曰希，抟之不得名曰微。此三者不可致诘，故混而为一”，认为一化为三，三合为一，“用则分三，本则常一”。三清尊神即本源于此，因此“三清”尊神在道教神仙体系中位为最尊，《道教义枢》卷七引《太真科》说：“大罗生玄元始三气，化为三清天也：一曰清微天玉清境，始气所成；二曰禹余天上清境，元气所成；三曰大赤天太清境，玄气所成。从此三气各生。”据《云笈七籖》和《道法会元》等道书记载，清微天玉清境，混洞太无元，其气始青，真道升圣境，天宝尊（元始天尊）治之；禹余天上清境，其气元黄，仙道升真境，灵宝天尊治之；大赤天太清境，其气玄白，人道升仙境，道德天尊居之。文曰：“此四种民天，即三界之上，灾所不及四种民天上有三清境。三清之上即是大罗天，元始天尊居其中，施化敷教。天宝君治在玉清境，清微天也。灵宝天尊治在上清境，即禹余天也，神宝君（道德天尊）治在太清境，即大赤天也。”（《云笈七签》卷三《道教本始部》）同时，道教的三清尊神还反应了道教“三洞真经”的神化。《云笈七签》卷六《三洞经教部》说:“《道门大论》云三洞者，洞言洞也。通玄达妙，其统有三，故云‘三洞’。第一洞真，第二洞玄，第三洞神。乃三景之玄旨，八会之灵章。”根据《道法会元》卷一《清微道法枢纽》关于清微神位的记载，清微圣祖玉清元始妙道上帝代表洞真经部，太玄辅之，传道教清微派；清微玄祖上清灵福玉宬大道君，代表洞玄经部，太平辅之，传灵宝派；清微始祖太清道德五灵玄老君代表洞神经部，太玄辅之，正一盟威之道通贯三洞，传道德派和正一派。

Three statues of bronze gilt are erected to the deities, located inside San Sheng Gong
San Qing, also named as the Three Pure Ones, are the most honourable deities in Taoism. These deities include Yu Qing Yuan Shi Tian Zun (玉清元始天尊), Shang Qing Ling Bao Tian Zun (上清灵宝天尊) and Tai Qing Dao De Tian Zun (太清道德天尊). The trinity is the manifestation of the “Three One” Theory of Tao. In the 42nd chapter of Taoist classic Dao De Jing (道德经), it was said that “Tao produced One, One produced Two, Two produced Three and Three produced All Things. All Things carry Yin and Yang, when these two are well integrated, that is harmony.” In the 14th chapter, Tao was also described as an essence “Looked at but cannot be seen; Listened to but cannot be heard; Reached for but cannot be obtained. These three senses cannot be analysed, but they mingle and act as one.”
It is believed that San Qing is the manifestation of Yuan Shi Tian Zun, who comes into being at the beginning of Jing Qi (精气) and resides in Da Luo Tian (大罗天). He is eternal, limitless and formless. He was incarnated into two other deities namely Ling Bao Tian Zun during the time of Tai Shi (太始) - a state of the beginning of “form”, and Dao De Tian Zun during the time of Tai Su (太素) - a state of the beginning of “substance”.