大般涅槃經義記 2.18

2.18

問曰：經說二乘能斷四住煩惱，比丘應無，今以何故請斷四住？解言：四住有麁、有細，麁者久無，細者猶在，故今請斷。

Question: The sūtras say that the two vehicles are able to sever the afflictions of the four entrenchments; the bhikṣus should not have them. Why do they now request the severance of the four entrenchments? Explanation: The four entrenchments have coarse and subtle aspects; the coarse ones have long been eliminated, but the subtle ones still remain, which is why they now request their severance.