俱舍論記 6.13

6.13

「雖無障用至種等於芽等」者，通。如涅槃等，望彼法生，雖無能障令不起用而亦為因，以果生時能皆無障故，所以名因。如無力國王雖無能損，亦得如前說我因國主而得安樂。此即通說一切無障諸能作因。若於能作因中就勝為言，非無生力。「如眼」等下，舉親勝力。

Regarding '[Although it lacks the capacity to obstruct ... like seeds with respect to sprouts, etc.]', this is the resolution: With respect to the arising of that dharma, [things] like nirvāṇa, although lacking the capacity to obstruct such that they prevent it from arising, are nonetheless causes because they are entirely unhindered when the fruit arises; therefore they are called causes. Just as a powerless king, although incapable of doing harm, can still be spoken of as before: 'It is due to the ruler that I have peace and happiness.' This is the general explanation of all unobstructed efficient causes (kāraṇa-hetu). If one speaks in terms of preeminence among efficient causes, it is not that they lack productive efficacy. From 'Just as the eye ...' onward, the direct and preeminent efficacy is adduced.