成唯識論述記 5.321

5.321

述曰：下立理也。忘念、散亂、惡惠三法若無，心必不能起諸煩惱，無此三故；如善心等。以忘念惠是癡等攝，散亂別有，故遍染心。如何要有忘念等三？

The Commentary states: Below, it establishes the reasoning. If the three dharmas of forgetfulness, distraction, and wrong wisdom are absent, citta definitely cannot give rise to the various afflictions, due to the absence of these three; just like wholesome citta, etc. Because forgetfulness and wisdom are subsumed under delusion and so forth, and distraction has a distinct existence, they are omnipresent in defiled citta. How must there be the three such as forgetfulness?