成唯識論述記 2.509

2.509

述曰：破空一已，又若擇滅體是一者，且如五部、一部九品，一品結斷時，應得餘未斷四部，八品擇滅無為，以體是一故。如彼已得一部，一品所得擇滅。

The Commentary states: Having refuted the oneness of space, further: if the substance of cessation through deliberation were one, then, for example, among the five categories, or among the nine grades of one category, when the bonds of one grade are severed, one should thereby attain the unconditioned cessation through deliberation of the remaining four unsevered categories and eight grades, because their substance is one—just like the cessation through deliberation already attained for that one category and one grade.