瑜伽師地論略纂 7.134

7.134

Within the twentieth aspect, there are four occurrences of the word "furthermore" (you): the first refers to being associated or non-associated with the essence of defilement and purification; the second refers to the faults of being associated or non-associated with defilement and purification; the lower two refer to the contemplation aspects of the fifth [basis] mentioned before, seeing that it is difficult to accomplish.