大般涅槃經集解 68.70

68.70

案僧亮曰：佛說有依空住者，而惑者言：有空法為有所依，即因緣住。因果同相，因無常故，果亦無常也。寶亮曰：既破諸外道所計竟，後還結言虛空是無物，故名常，非是有法；佛性常，而是有故，非三世攝也。

Sengliang comments: The Buddha says that existence abides in reliance upon space, yet the confused say: there is a phenomenon of space that serves as what existence relies upon, which is abiding through causes and conditions. Cause and effect share the same characteristic; because the cause is impermanent, the effect is also impermanent. Baoliang says: Having completed the refutation of the reckonings of the non-Buddhists, he then concludes by stating that empty space is devoid of things and therefore called permanent, not being an existent phenomenon; the buddhadhātu is permanent and yet existent, and therefore is not subsumed under the three times.