宋高僧傳 24.55

24.55

系曰：小乘尚開食五淨物，薏苡非五穀正食也。疑其冥官因機垂誡，嫌于時比丘太慢戒法，故此嚴警開制。實諸佛常法也，非後人之加釀焉。

An appraisal says: The Hīnayāna still allows the consumption of the five purified foods, and Job's tears are not among the five proper staple grains. It is suspected that the official of the underworld was imparting admonition according to the capacity of beings, displeased that the bhikṣus of the time were too lax regarding the rules of the precepts; hence this stern warning about allowances and prohibitions. This is in truth the constant law of all Buddhas, not a later fabrication.