大般涅槃經集解 47.24

47.24

案僧亮曰：涅槃有大小，亦多義。今唯大涅槃常樂我淨四義是定，餘義皆不定也。如有為法，無常苦定，餘義不定也。二端不可燒者，明真應二身不可滅也。寶亮曰：此下乃至非說非非說，當知如來之身，非如來、非不如來，是故如來不定。

Sengliang comments: Nirvāṇa has greater and lesser forms, and also many meanings. Now, only the four meanings of the mahānirvāṇa—permanence, bliss, self, and purity—are determinate; the other meanings are all indeterminate. Just as with saṃskṛta phenomena, impermanence and suffering are determinate, while other meanings are indeterminate. As for the two ends not being burnable: this clarifies that the two bodies, the true and the responsive, cannot be extinguished. Baoliang says: From here down to 'neither preached nor not preached', one should know that the Tathāgata's body is neither Tathāgata nor non-Tathāgata; therefore the Tathāgata is indeterminate.