大般涅槃經集解 38.40

38.40

案僧亮曰：此下答果上有口過之難也。明以知方便故，莫問語之麁細，但使有益便說、無益則不，此非二乘所知也。僧宗曰：此答中有三意，此第一先明善照機宜、動必有益也。寶亮曰：答第二難。明所以發此言者，要使是時是法必有利耳，諸佛豈空發言乎？

Sengliang comments: From here on, it answers the objection concerning fault of speech in the fruition [stage]. It clarifies that because he knows upāya, regardless of whether words are coarse or refined, he speaks whenever there is benefit, and does not when there is no benefit; this is not something the two vehicles can understand. Sengzong says: There are three points in this answer; this first one clarifies that through skillful discernment of what is suitable for the faculties, every action necessarily brings benefit. Baoliang says: This answers the second objection. It clarifies that the reason he uttered these words was solely to ensure that this time and this teaching would necessarily bring benefit; how could the Buddhas utter words in vain?