大方廣佛華嚴經隨疏演義鈔 33.53

33.53

疏「三相對二義」者，一即真如隨緣能成萬法，方是真如。二即真如不變方能現染，若變性淨不能現染，若不現染無隨緣德。

Regarding the commentary's "third, the two meanings of mutual contrast": first, that tathatā, acceding to conditions, is able to accomplish the myriad phenomena, is precisely what makes it tathatā. Second, only because tathatā is unchanging is it able to manifest defilement; if its nature were altered, being pure it could not manifest defilement, and if it could not manifest defilement, it would lack the virtue of acceding to conditions.