大乘起信論義疏 1.79

1.79

問曰：修習而得解者，何故空滅乎？答曰：是妄解故，不得成佛。解故斷惑，體是妄解，故終歸滅亡。云何得知明解隨滅？《涅槃經．四相品》中言「譬如男女大小器中，悉滿中油，燃燈油盡，明亦隨滅，燈爐猶在。」下合中言「油盡者喻煩惱滅；明喻智慧，慧雖滅已猶法身存。」此文顯矣。終心之中皆悉滅故，名非究竟覺也。自下第二釋究竟覺。言「得見心性」者，謂真識也。「心即常住」者，始覺是也。名「究竟覺」者，覺心源故修歸圓覺也。

Question: Why should an understanding attained through cultivation and practice vanish in emptiness? Answer: Because it is a deluded understanding, it cannot become Buddha. Through understanding, perplexities are severed, but its essence is a deluded understanding, so in the end it must return to extinction. How is it known that the brilliant understanding perishes in accordance with it? In the 'Chapter on the Four Marks' of the Nirvāṇa Sūtra, it says: 'Just as when vessels large or small of men or women are all filled with oil, when the lamp is lit and the oil is exhausted, the flame likewise perishes, yet the lamp basin still remains.' In the application below, it says: 'The exhaustion of the oil is a metaphor for the cessation of afflictions; the flame is a metaphor for wisdom; although wisdom has ceased, the dharmakāya still remains.' This text makes it clear. Because within the concluding mind they all cease, it is called non-ultimate enlightenment. Below, the second part explains ultimate enlightenment. Regarding 'attaining the seeing of the mind-nature,' this refers to the true consciousness. Regarding 'the mind is then permanently abiding,' this is initial enlightenment. It is called 'ultimate enlightenment' because awakening to the mind's source, cultivation returns to perfect enlightenment.