大般涅槃經集解 16.44

16.44

案僧亮曰：向以律募，今以經要也。呪術譬般若，三十三天譬涅槃也。藥者譬常住，當共行經以求常，故譬食也。

Sengliang comments: Previously he recruited through the Vinaya; now he uses the essentials of the sūtras. The incantations symbolize prajñā; the Trāyastriṃśa Heaven symbolizes nirvāṇa. The medicine symbolizes permanence. They are to practice the sūtras together to seek permanence; hence it is compared to consuming [it].