瑜伽論記 5.50

5.50

又依無上依經說：眾生界是如來藏，眾生共有是無為故，據如此義說眾生界不增不減，彼經意真起妄立眾生界，故說真如名眾生界，二乘雖入無餘諸蘊滅盡，而此界體常存不滅，據如此義說眾生無增無減。

Furthermore, relying on the Anuttarāśraya-sūtra, it is said that the realm of sentient beings is the tathāgatagarbha; because it is shared by all sentient beings and is unconditioned, based on this meaning it is said that the realm of sentient beings neither increases nor decreases. The intention of that sūtra is that the real gives rise to the false to establish the realm of sentient beings; hence it says tathatā is called the realm of sentient beings. Although [practitioners of] the two vehicles enter [nirvāṇa] without remainder and all aggregates are eradicated, the substance of this realm eternally remains and is not annihilated; based on this meaning it is said that sentient beings neither increase nor decrease.