宋高僧傳 4.34

4.34

系曰：「海龍之宮自何而有經本耶？」通曰：「經云龍王宮殿中有七寶塔，諸佛所說諸深義，別有七寶篋滿中盛之，謂十二因緣、總持、三昧等。良以此經合行世間，復顯大安、曉公神異，乃使夫人之疾為起教之大端者也。」

The appraisal says: 'How was the text of the sūtra in the ocean dragon's palace?' The resolution states: 'The sūtras say that in the dragon king's palace there is a seven-jeweled stūpa, and the profound meanings spoken by the Buddhas are separately stored to the brim in seven-jeweled caskets, namely the twelve links of dependent origination, dhāraṇīs, samādhis, and the like. Truly because this sūtra was suited to circulate in the world, and further to manifest the supernatural wonders of Da'an and Lord Wonhyo, the queen's illness was caused to serve as the grand occasion for the teaching to arise.'