俱舍論疏 25.32

25.32

論「思法等四至應是進非退」，明先是退姓至無學進至思等，後退果時還住退性，不住思等。

On the Śāstra's statement: "The four, such as the dharma of reflection ... this would be advancing, not falling away": This explains that if one was originally of the lineage liable to fall away and, upon reaching the adept stage, advanced to reflection and so forth, when one later falls away from the fruit, one returns to abide in the lineage liable to fall away, and does not abide in reflection and so forth.