俱舍論記 17.149

17.149

「毘婆娑師至後輕於前」者，此即第二師解。由前煩惱能引後業，故後業障輕前煩惱。由前業障引後異熟，故後異熟輕前業障。以前是本，後是末故。故《婆沙》云「問：如是三障何者最重？或有說者，異熟障重。所以者何？因時可轉，果時不可轉故。復有說者，業障最重。所以者何？業障能引異熟障故。如是說者煩惱障重，以煩惱能引業障，業障復能引異熟障，如是皆以煩惱為本，是故最重。

"The Vaibhāṣikas say: Up to: The subsequent is lighter than the preceding": This is the explanation by the second master. Because the preceding affliction can project the subsequent karma, the subsequent obstacle of karma is lighter than the preceding affliction. Because the preceding obstacle of karma projects the subsequent ripening, the subsequent obstacle of ripening is lighter than the preceding obstacle of karma. Because the preceding is the root and the subsequent is the branch. Therefore the Vibhāṣā says: "Question: Among these three obstacles, which is the heaviest? Some say: The obstacle of ripening is heavy. Why is that? Because at the time of the cause it can be averted, but at the time of the fruit it cannot be averted. Others say: The obstacle of karma is heaviest. Why is that? Because the obstacle of karma is able to project the obstacle of ripening. The authoritative statement is: The obstacle of affliction is heavy, because affliction is able to project the obstacle of karma, and the obstacle of karma in turn is able to project the obstacle of ripening; thus all take affliction as their root, and therefore it is the heaviest."