大般涅槃經集解 23.44

23.44

案僧亮曰：上說涅槃能度生死，非餘契經，以此釋之也。佛之真身是實，涅槃說實，見實則生死盡也。應身非實，契經以之為實，不見實故，生死不盡也。法瑤曰：蛇脫皮者，止明雙樹一迹耳。雖現捨生死，而迹無生滅，法身常一也。僧宗曰：答第十九問，向云乘涅槃船濟度眾生，實無生滅。物以王宮之生、雙樹之滅為疑，故以此譬拂滯也。

Sengliang comments: Above it was said that nirvāṇa can deliver from saṃsāra, whereas other sūtras cannot; this explains it. The Buddha's true body is real; nirvāṇa explains the real, and when one sees the real, saṃsāra is exhausted. The response body is not real; other sūtras take it as real, and because they do not see the real, saṃsāra is not exhausted. Fayao comments: The snake shedding its skin merely clarifies the single trace at the Twin Trees. Although manifesting the discarding of saṃsāra, the trace has no arising or ceasing, and the dharmakāya is eternally one. Sengzong comments: Answering the nineteenth question: earlier it was said that boarding the ship of nirvāṇa to ferry sentient beings across is truly without arising or ceasing. Beings doubted this because of the birth in the royal palace and the extinction at the Twin Trees, so this parable is used to dispel their obstruction.