瑜伽師地論略纂 11.58

11.58

論解同事因云「若清淨品者，此簡雜染同事因」。若爾，何別雜染中不言？若雜染品法同事因言，此乃影顯。今此已明，前不須解，不皆身繁文。又此言若清淨，即知前雜染同事因，故須簡也。

Regarding the treatise's explanation of the co-operating cause, saying "as for the pure category, this differentiates it from the co-operating cause of defilements": If so, why is it not distinguished in the defiled category? If the co-operating cause for defiled phenomena was spoken of, this was indicated by implication. Now that it is clarified here, it did not need to be explained previously, so as not to encumber the text everywhere. Furthermore, by stating "if it is pure," one thereby knows the previous co-operating cause of defilements; thus it needed to be differentiated.