俱舍論疏 25.26

25.26

論「雖俱有退至所成堅故」，退姓、退果並非先也。謂先學位是退種姓，至無學位練根進成思種姓等，此種性等有退種姓及退果義。若先學位是思種姓，至無學位進思護等有退種姓。至思種姓無退果義，及退思種姓義，學、無學道所成堅故。護等准此。《婆沙》一百八十二云「尊者設摩達多說：退阿羅漢時，唯得未來先所捨學果，不得過去。所以者何？以彼畢竟不現前故。上地沒生下亦爾。」又云「摩訶僧祇說：預流果有退。」

On the Śāstra's statement: "Although both involve falling away ... because of the firmness of what has been accomplished": Falling away from lineage and falling away from fruit do not apply to what was originally attained. That is, if one was originally of the lineage liable to fall away in the stage of a trainee (śaikṣa), and upon reaching the stage of an adept (aśaikṣa) advanced through training faculties to become of the lineage of reflection and so on, these lineages admit both of falling away from lineage and falling away from the fruit. If one was originally of the lineage of reflection in the stage of a trainee, and upon reaching the stage of an adept advanced from reflection to preservation and so forth, there is falling away from lineage. But upon reaching the lineage of reflection, there is no falling away from the fruit, nor falling away from the lineage of reflection, because what has been accomplished through both the path of the trainee and the path of the adept is firm. Preservation and so forth should be understood accordingly. The Vibhāṣā, fascicle 182, says: "Venerable Śamathadatta said: 'When one falls away from the fruit of an arhat, one only obtains the previously relinquished trainee fruit in the future, not in the past. Why is that? Because that [past fruit] can never become present. The same applies when dying in a higher stage and being reborn below.'" It also says: "The Mahāsāṃghikas say: 'The fruit of stream-entry admits of falling away.'"