大般涅槃經義記 2.37

2.37

Next is discerning the meaning: permanence, bliss, self, and purity in principle truly pervade all buddhadharmas; yet now, distinguishing what is hidden and revealed, 'self' is treated specifically in terms of the person, while the other three are treated in terms of dharmas. 'The self is the Buddha': sovereignty is called 'self'; since the function of sovereignty resides in the Buddha-person, it is spoken of as 'self.' Furthermore, 'self' is a distinct name for a person; hence, it is spoken of as 'self' with respect to the Buddha-person. 'Permanence is the dharmakāya': the dharmakāya is the Buddha's substance, which is realized through the revelation of the fundamental Dharma; its nature originated from antiquity, and its substance is free from change; because the meaning of permanence is distinctly demonstrated, it is spoken of as 'permanent.' 'Bliss is nirvāṇa': nirvāṇa is cessation, which is the cessation of and departure from all suffering; because the meaning of serene bliss is distinctly demonstrated, it is spoken of as 'bliss.' 'Purity is the Dharma': this refers to the substance of the Dharma jewel among the Three Jewels, which is able to remedy defilement; hence it is spoken of as 'pure.'