大乘起信論廣釋卷第三．四．五 5.15

5.15

論。如是眾生至亦無得淨　釋曰。下合有三。初正合前喻。次顯行所以。後善行順真。此初也。真如等者。初顯真性淨。離偽名真。無二曰如。有恒沙德故名為法。無礙名空。無染名淨。而有等者。次顯真相。染真及煩惱。皆眾生有之。眾生之垢妄翳真如。非謂真如性自有垢。若人已下後顯藉緣。淨以有垢故。不以方便熏真滅妄終無得淨。

Treatise: In this way, sentient beings [...] will never attain purity.
Commentary: In the application below there are three parts: first, directly applying the preceding simile; next, revealing the reason for the practice; later, wholesome practices according with the real. This is the first. Regarding "tathatā," etc.: First, it reveals that the real nature is pure. Being free from falsehood is called "true" (tatha); being non-dual is called "such" (tā). Possessing virtues numerous as the sands of the Ganges, it is called "dharma." Being unimpeded is called "empty"; being undefiled is called "pure." Regarding "yet there are," etc.: Next, it reveals the marks of the real. Defilement of the real and afflictions are all possessed by sentient beings. The defilements of sentient beings falsely obscure tathatā; it is not that the nature of tathatā itself has defilement. From "if a person" below: Afterwards, it reveals reliance on conditions. Because purity has defilement, unless one uses skillful means to perfume the real and extinguish the false, one will never attain purity.