大般涅槃經義記 3.117

3.117

第四，同化有益喻中，半國、不虛，兩釋同前。《大涅槃經》所詮常法終必同修，名「呪所致不死之藥當共分食」。

Fourth, in the metaphor of there being benefit in conforming to the transformation: 'half the state' and 'not in vain' have the two explanations as before. The eternal Dharma expressed by the Mahāparinirvāṇa Sūtra will ultimately be cultivated together; this is called 'the medicine of immortality brought about by dhāraṇī-spells shall be divided and consumed together.'