大乘義章 18.33

18.33

次論生死涅槃一異。一異如何？分別有三：一就緣說緣。斷生死體得涅槃性，生死涅槃體性全別。如經中說「本有今無，本無今有，三世有法無有是處。」正當此門。又經中說「涅槃互無」，亦當此門。二約緣論實。轉生死體即是涅槃，非全別體。良以迷時迷涅槃性為生死故，是故解時解生死體即是涅槃。如人迷時正方為邪，及至解時邪方即正；亦如夜闇見繩為蛇，及後明時蛇即是繩。故經說言「凡夫未成佛，菩提為煩惱。聖若成佛時，煩惱即菩提。」菩提既然，涅槃亦爾。三就實論實。生死之體即是涅槃，不得還轉。如蛇是繩，豈待至明？生死涅槃一異如是，不得偏取（此六門竟）。

Next is discussing the identity and difference of saṃsāra and nirvāṇa. How are they identical or different? There are three distinctions: First, speaking of conditions in terms of conditions. Severing the substance of saṃsāra, one attains the nature of nirvāṇa; the substance and nature of saṃsāra and nirvāṇa are completely distinct. As stated in the sūtra: "Originally existent, now non-existent; originally non-existent, now existent; that there are dharmas existing throughout the three times is impossible"—this precisely corresponds to this gate. Furthermore, as the sūtra states, "nirvāṇas are mutually non-existent," which also corresponds to this gate. Second, discussing the real in relation to conditions. Transforming the substance of saṃsāra is itself nirvāṇa, not a completely different substance. Indeed, because when deluded, one mistakes the nature of nirvāṇa for saṃsāra, therefore when understanding, one understands that the substance of saṃsāra is itself nirvāṇa. Just as when a person is deluded, the correct direction is taken as wrong, and when they understand, the wrong direction is itself the correct one; also like seeing a rope as a snake in the dark of night, and later when it is bright, the snake is itself the rope. Thus the sūtra states: "Before an ordinary person achieves Buddhahood, bodhi is affliction. When a noble achieves Buddhahood, affliction is itself bodhi." If bodhi is like this, nirvāṇa is also like this. Third, discussing the real in terms of the real. The substance of saṃsāra is itself nirvāṇa, with no reversal or transformation possible. Just as the snake is the rope, how could it wait for daybreak? The identity and difference of saṃsāra and nirvāṇa are like this; one must not cling to one side (this concludes the sixth gate).