瑜伽論記 23.221

23.221

為令已下，是其第四却明修空方便。言四種雜染，謂復有因性故等者，即四故字為四染也。言說有二：一者、隨逐音聲解言說，二者、隨逐法行言說者。次前前行計，又能善知量離諸染而起言說，由彼文勢故云言說有二等也。

From 'in order to make' downward, the fourth part conversely clarifies the expedient means of cultivating emptiness. In the statement 'four kinds of defilements, meaning because there are further causal natures,' and so forth, the four occurrences of the word 'because' constitute the four defilements. Regarding 'discourses are of two kinds: first, discourses that follow sound; second, discourses that follow the practice of Dharma': following the preceding mental reckoning of practices, one can also well know the proper measure and initiate discourses while separated from all defilements; by the force of that text, it says 'discourses are of two kinds,' and so forth.