大乘起信論義疏 2.18

2.18

自下第三結難知，唯如來能知故也。故《大經》言「十住菩薩見終不見始，佛乃窮了見始見終。」自下第二隨對治，此中有三：一者、法說；二者、「如木中」下，開譬；三者、「眾生亦爾」下，合喻。言「有因有緣」者，因者內心，緣謂外緣。譬意者，木雖有火，不能自燒；眾生雖有真如之性，不能獨熏自成涅槃。合中可解。言「示教利喜」者，四諦三轉法輪也。示猶示轉，教猶勸轉，利喜是其猶證轉也。示轉者，示苦、示集、示滅、示道，名示轉也。言勸轉者，苦應知、集應斷、道應修、滅應證。言證轉者，苦我已知、集我已斷、道我已修、滅我已證也。示可當相，示苦令知、教集應斷、道利應修、滅喜應證也。以此四諦入道之詮，故以四諦向涅槃道也。

Below is the third, concluding that it is difficult to know, for only the Tathāgata can know it. Therefore, the Mahāparinirvāṇa Sūtra says: 'Bodhisattvas of the ten abodes see the end but do not see the beginning; only the Buddha completely understands and sees both the beginning and the end.' Below is the second, on conforming to counteragents, which contains three parts: first, the exposition in terms of Dharma; second, from 'Just as within wood' onward, opening the analogy; third, from 'Sentient beings are also like this' onward, matching the analogy. 'Having causes and conditions' means: the cause is the internal mind; conditions refer to external conditions. The meaning of the analogy is that although wood contains fire, it cannot burn of itself; although sentient beings possess the nature of tathatā, it cannot perfume alone to accomplish nirvāṇa by itself. The matching can be understood. 'Showing, instructing, benefiting, and gladdening' refers to the three turnings of the wheel of the Dharma regarding the four truths. 'Showing' is like the turning of demonstration; 'instructing' is like the turning of exhortation; 'benefiting and gladdening' is like the turning of realization. The turning of demonstration means demonstrating suffering, demonstrating accumulation, demonstrating cessation, and demonstrating the path—this is called the turning of demonstration. The turning of exhortation means: suffering should be known, accumulation should be severed, the path should be cultivated, and cessation should be realized. The turning of realization means: suffering has been known by me, accumulation has been severed by me, the path has been cultivated by me, and cessation has been realized by me. Demonstration corresponds to the marks: showing suffering to make it known, instructing on accumulation that it should be severed, benefiting through the path that it should be cultivated, and gladdening in cessation that it should be realized. Because these four truths are the vehicles for entering the path, one heads toward the path of nirvāṇa by means of the four truths.