大乘起信論裂網疏 2.51

2.51

超過菩薩地者，等覺後心，入於金剛喻定也。法空無漏妙觀察智，名究竟道。從初證法身後，分分增進，至此滿足，令異熟識中有漏種子捨無不盡，轉成菴摩羅識，即與大圓鏡智忽得相應，故云一念相應覺心初起也。始名為覺者，釋成究竟始覺義也。遠離覺相者，釋成即是本覺，無別覺起義也。微細分別究竟永盡者，無間道中，捨異熟識種也。心根本性常住現前者，解脫道中，證本具法身也。如者，本覺真如之性。來者，始覺合本之修。始本合一，故為如來；始本兩忘，故名究竟覺也。

"Surpassing the bodhisattva stages" refers to the final thought of equal awakening, entering the diamond-like samādhi (vajropamasamādhi). The untainted wondrous observing wisdom of the emptiness of dharmas is called the ultimate path. From first realizing the dharmakāya onwards, one progresses incrementally, reaching fulfillment here, causing all tainted seeds within the vipāka-consciousness to be abandoned without remainder, transforming it into the amalavijñāna, whereupon it suddenly accords with the great round mirror wisdom; hence it is said, "with one thought in accord, the awakening mind first arises." "Only then is it named awakening" explains the meaning of ultimate initial awakening. "Far leaving behind the marks of awakening" explains the meaning of its being nothing other than original awakening, with no separate awakening arising. "Subtle conceptual differentiation is ultimately and forever exhausted" means abandoning the seeds of the vipāka-consciousness within the unimpeded path (ānantaryamārga). "The fundamental nature of the mind is eternally abiding and manifested before one" means realizing the inherently possessed dharmakāya within the path of liberation (vimuktimārga). "Thus (tathā)" is the nature of the tathatā of original awakening. "Come (āgata)" is the cultivation wherein initial awakening unites with the original. Initial and original are united as one, and therefore one is a Tathāgata; initial and original are both forgotten, and therefore it is named ultimate awakening.