成唯識論述記 5.447

5.447

述曰：解阿羅漢無所由義，非見道斷，任運生故，非分別故。然此染故，非是不斷，不斷之法並無漏故，明是修斷，於何時斷。

The Commentary states: This explains the reason why it does not exist in an arhat. It is not severed by the path of vision because it arises spontaneously and is not conceptualized. Yet because it is defiled, it is not non-severable, for dharmas that are not to be severed are all uncontaminated; it is clear that it is severed by cultivation, [and it will be shown] at what time it is severed.