俱舍論疏 6.120

6.120

論「無覆無記至二一為因」，次明無覆無記為因差別。准義同類異熟九品展轉為因，餘二與等、勝為因，非加行生加行生故。

The treatise says, "Unobscured-unrecordable [...] two and one as causes," which next clarifies the distinctions among unobscured-unrecordable [phenomena] in serving as causes. According to the principle, the nine grades of vipāka of the same kind serve mutually as causes; the remaining two serve as causes for the equal and superior, because they are not born of application and born of application [respectively].