大般涅槃經集解 5.112

5.112

案僧亮曰：純陀重請之意，謂佛慈悲以應苦眾生；今我現苦，所以願佛留慈應也。佛答意，以去必有益，住則無益也。諸佛法爾者，以生滅為苦、無生滅為樂，故我滅此生滅之苦也。

Sengliang comments: Cunda's intention in making the request again was that the Buddha's loving-kindness and compassion respond to suffering sentient beings; now I manifest suffering, which is why I vow for the Buddha to remain in compassion to respond. The Buddha's intent in responding is that departing will certainly have benefit, while remaining would have no benefit. "Such is the nature of all buddhas" means that taking arising and ceasing as suffering and non-arising and non-ceasing as bliss, I therefore extinguish this suffering of arising and ceasing.