大般涅槃經集解 8.70

8.70

案僧宗曰：若於解者，不假移譬。但悟有先後，致說有重複，洗沸人疑。疑謂現見如來，始王宮生、終雙樹滅，豈言不滅？故借天樹三變以為喻也。

Sengzong states: For those who understand, there is no need to employ another simile. But because awakening comes earlier to some and later to others, the teaching is repeated to wash away people's doubts. Doubting, they say: seeing the Tathāgata with one's own eyes, born in the royal palace at first and extinguished at the Twin Trees in the end, how can it be said that he is not extinguished? Therefore, the three transformations of the celestial tree are borrowed as a simile.