大般涅槃經義記 4.248

4.248

From here below is the third [part], revealing the Dharma in response to them. In this text, it fully answers seven questions: answering the first question clarifies the fruit of nirvāṇa; answering the latter six questions clarifies the causes of nirvāṇa. Clarifying the fruit of nirvāṇa answers the question above, "Why does he further manifest ultimate nirvāṇa?" What is the meaning of the question? If the Tathāgata now ultimately enters the nirvāṇa of complete extinction, why does he continually manifest in the world to teach and transform sentient beings? The Buddha now answers it, clarifying that he never ultimately enters nirvāṇa, and therefore continually manifests in the world, which is truly worthy of being called Great Nirvāṇa. Question: Previously, in the "Lamentation Section", the fruit of nirvāṇa was already fully clarified; why is it clarified again here? Answer: Previously, the eternity of the essence of nirvāṇa was explained, but the eternity of the function of nirvāṇa had not yet been proclaimed; therefore it must be clarified. Furthermore, previously the causes of bodhi were clarified; here, if one does not raise the fruit of nirvāṇa to reveal the causes in response to it, the causes would be conflated with the previous ones; to distinguish these causes, one must raise the fruit of nirvāṇa. Moreover, above, in explaining the causes of bodhi, most cases raised the fruit to reveal the cause in response to it—just as previously, in clarifying the attainment of long life, the fruit was raised to reveal the cause—this is similar to that, so the fruit must be raised.