瑜伽論記 18.236

18.236

前中，云：謂若略說，清淨因故等者，景云：若了二名起諸過患，即便證入二空道理，名清淨因。觀察二名善知自相，謂以四蘊及以音聲為性，名觀自相。迷執二名廣興煩惱，發業得報，名雜染因。由觀此故名觀雜染因。

In the former, it says: "To state in brief, because of the cause of purity" and so forth. Jing says: If one comprehends the faults arisen from the two names, one immediately realizes and enters the principle of the two emptinesses, which is called the cause of purity. Observing the two names and properly knowing their self-characteristics—namely taking the four aggregates and sound as their nature—is called observing self-characteristics. Deludedly grasping at the two names, extensively giving rise to afflictions, initiating karma and obtaining retribution, is called the cause of defilement. Because of observing this, it is called observing the cause of defilement.