俱舍論記 29.27

29.27

「諸惑斷已至之所蔽伏」者，釋第二章。由未至定，九無間道諸惑斷已，離染位中方得根本四種無量。於此離染後位之中，雖遇起惑強緣，而非瞋等之所蔽伏。以此能令已斷更遠，說能治障。應知無量，若據加行似修，在欲、未至；若據根本修成，在四本定。

Regarding "after the defilements are abandoned, up to: overwhelmed by them": this explains the second heading. After the defilements have been abandoned by the nine uninterrupted paths of the anāgamya, it is in the state of detachment that one first attains the four fundamental immeasurables. In this subsequent state of detachment, even if one encounters strong conditions that would arouse defilement, one is not overwhelmed by hatred and the like. Because these cause what has already been abandoned to become even further removed, they are said to be able to counteract the hindrances. One should know that as for the immeasurables, if considered in terms of preparatory resembling cultivation, they are in the desire realm and the anāgamya; if considered in terms of fundamental perfection through cultivation, they are in the four fundamental dhyānas.