大般涅槃經義記 4.248

4.248

自下第三對之顯法，於此文中具答七問，答初一問明涅槃果，答後六問明涅槃因。明涅槃果，答上問中云何復示現究竟於涅槃。問意如何？如來今者究竟入於盡滅涅槃，云何復常示現世間教化眾生？佛今答之，明己終不究竟涅槃，故常示現在於世間，真得名為大涅槃矣。問曰：向前〈哀嘆章〉中已具明其涅槃果竟，今此何故重復明乎？解云：前辯涅槃體常，未曾宣說涅槃用常，故須明之。又復上來明菩提因，今此若不舉涅槃果對之顯因，因與前濫，為別其因，故須標舉涅槃之果。又復上說菩提因中多皆舉果對之顯因，是故前明得長壽中舉果顯因，此亦似彼故須舉果。

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.