大般涅槃經義記 5.243

5.243

文中初言「出大涅槃」辯法同喻，「猶如醍醐」舉喻以牒，醍醐喻性，「性即如來」約喻顯法，此乃即於法身如來，非即報身，報身功德不及此經，故不即之。「以是義」下嘆法同喻，唯嘆如來，略不嘆性。如彼醍醐一切諸藥悉入其中，如來法身亦復如是，一切功德悉入其中，是故說言「如來功德無量無邊」。

In the text, the opening phrase, "emerges the Great Nirvāṇa," analyzes the principle alongside the metaphor; "just like clarified butter" adduces the metaphor to reiterate it—clarified butter symbolizes the nature; "the nature is the Tathāgata" relies on the metaphor to reveal the principle. This directly refers to the dharmakāya Tathāgata, not to the reward body; the merits of the reward body do not equal this sūtra, hence it does not refer to it. From "for this reason" downward, it praises the principle alongside the metaphor, praising only the Tathāgata while omitting praise of the nature. Just as in that clarified butter all medicines are subsumed, the Tathāgata's dharmakāya is also like this, with all merits subsumed within it; therefore it is said, "The Tathāgata's merits are immeasurable and boundless."