俱舍論疏 19.38

19.38

論「若不相應至恒現前故」，次反釋也。若相應法是隨眠者，起時能覆障善令不得生，若不起時善心容起。若隨眠體是不相應，即恒相續在身不斷，若能障善，善無起時，以不相應恒現前故。

Regarding the treatise from "If it were disassociated... up to... constantly present", next is the explanation through negation. If a factor associated [with thought] were the anuśaya, when it arises it could obstruct the wholesome so that it cannot arise, and when it does not arise, a wholesome mind would have room to arise. But if the substance of anuśaya were disassociated, it would constantly continue in the continuum without interruption; if it could obstruct the wholesome, wholesome [states] would never have an occasion to arise, because what is disassociated is constantly present.