俱舍論疏 6.103

6.103

論「定依有漏至皆互為因」，答也。前說同類因唯自地者，依有漏說。若依無漏，九地展轉為因。

The treatise says: "Definitively based on the contaminated... all mutually serve as cause." This is the answer. What was said earlier—that a similar cause belongs only to its own stage—is stated based on the contaminated. If based on the uncontaminated, the nine stages mutually serve as cause for one another.