大乘起信論義記 2.242

2.242

In citing proof, "relying on this meaning... nirvāṇa" means: relying on this gate of the mark of sameness, since the aforementioned fundamental and derivative non-enlightenment are fundamentally identical to tathatā, it is said that the nature of all sentient beings is intrinsically nirvāṇa and does not undergo extinction again. Hence a sūtra says: "All sentient beings are already the mark of nirvāṇa and do not become extinct again." As for "the dharma of bodhi... unobtainable": relying on this gate of the mark of sameness, since the aforementioned incipient and innate enlightenments are precisely tathatā, the bodhi of the buddhas is not obtained through cultivation. Furthermore, previously, with respect to non-enlightenment being identical to tathatā, sentient beings have from of old entered nirvāṇa; now, with respect to enlightenment also being identical to tathatā, the bodhi of all buddhas is nothing newly obtained. "Not a mark to be cultivated" means that, looking back to the aforementioned nirvāṇa, it is not cultivated and revealed through revealing causes. "Not a mark to be made" means that, looking back to the aforementioned bodhi, it is not produced by generative causes. "In the end is unobtainable" means that these two fruits are fundamentally possessed as naturally pure; hence they are unobtainable.