大般涅槃經義記 7.215

7.215

次對凡夫樂受辯異，說樂濫彼故須辯異，先舉，次列，下辯其異。「凡樂無常，是故無樂」簡凡異聖。「諸佛常樂，故名大樂」彰聖異凡。

Next, distinguishing it by contrast with the pleasant sensations of ordinary persons: because speaking of bliss might be conflated with that, it must be distinguished; it first raises it, next enumerates it, and below analyzes its distinction. "The bliss of ordinary persons is impermanent, therefore it is without bliss" distinguishes the ordinary from the noble. "All buddhas have permanent bliss, therefore it is called great bliss" reveals how the noble differs from the ordinary.