大乘起信論廣釋卷第三．四．五 4.65

4.65

[Treatise:] Because the dharma of tathatā [constantly perfumes, delusions are extinguished and the dharmakāya is revealed, producing the perfuming of activity;] hence it is without interruption.
[Commentary:] This adduces the reason to answer the previous question. "Because the dharma of tathatā," and so forth, explains the sense of the first question: namely, that defiled perfuming arises in opposition to principle and is an impermanent dharma; hence it is without interruption, so it says tathatā constantly perfumes, and so forth. "The dharmakāya is revealed," and so forth, answers the latter question: if one has not yet attained buddhahood, it perfumes through substance; if one has already attained buddhahood, although the substance is without defilement, it perfumes through activity because there are defiled beings. That is, within the two marks, it is the distinct activity of the inconceivable karma of initial awakening's responsive transformation. Furthermore, the Buddha's dharmakāya and sentient beings are non-dual; although the Buddha has no defilement, sentient beings have defilement. Since there are no distinct sentient beings outside the dharmakāya, the substance of the dharmakāya also inherently possesses defilement. That is, within the four mirrors, it is the pervasive activity of the condition-perfuming mirror of the original awakening dharmakāya. Explaining it in this way is extremely complete and luminous in principle, and only then can one fully capture the profound import of the treatise; it has never been seen in any of the commentaries.