俱舍論疏 7.129

7.129

論「雖爾厭倦至容起加行」，答也。加行善心違煩惱故，極厭煩惱生加行善。三心不能生極厭故，不順不能生加行善。

The Śāstra says, "Although that is so, through disgust and weariness ... it is possible to give rise to the preparatory": this is the answer. Because the preparatory wholesome mind opposes afflictions, one gives rise to the preparatory wholesome out of extreme revulsion toward afflictions. Since the three minds cannot produce extreme revulsion, because they are not in accord, they cannot produce the preparatory wholesome.