大般涅槃經集解 8.68

8.68

案僧亮曰：向乘涅槃船，物見其滅，實則不滅。近識未悟，移譬顯之。如蛇脫皮，非為實死。如來亦爾，現滅非真，借以為喻。

Sengliang states: Previously one boarded the ship of nirvāṇa, and beings perceived his extinction, but in reality he is not extinguished. Since those of shallow understanding have not yet awakened, another simile is employed to reveal it. Just as a snake sheds its skin and does not truly die, the Tathāgata is likewise: manifesting extinction is not real; it is borrowed as a metaphor.