俱舍論疏 28.187

28.187

論「此非決定至決定得者」，答也。加行入見道時不定。若未離染入見道者，未得根本定，故不得也。若超越者即得根本，以不定故，不言加行得也。若聖人離下染時，決定皆得根本無漏，以決定故，唯說離染得也。

The passage of the śāstra from 'This is not invariable...' down to '...that which is invariably acquired' is the answer. Entering the path of seeing through application is not invariable. If one enters the path of seeing without yet detaching from defilement, one has not yet acquired the fundamental attainment, and therefore does not acquire it. If one is a leap-over [practitioner], one immediately acquires the fundamental; because it is not invariable, it is not said to be acquired through application. When a noble one detaches from lower defilement, they invariably acquire all fundamental untainted [attainments]; because it is invariable, it is spoken of solely as acquired through detachment from defilement.