瑜伽論記 16.284

16.284

備云：一來練根不證不還者，即有二因，不還練根。進離欲者，謂練根時作意求進斷色惑，不證應果者，出界難故，起作事多故。轉根已後，一切皆證者，謂轉得利根已。若斷色惑及證羅漢一切皆得，或可預流等得轉根已。斷惑證果一切皆得，非獨不還。

Bei says: 'A once-returner refining the faculties does not realize the non-returner fruit due to two causes. When a non-returner refines their faculties and advances to separate from desire, it means that at the time of refining the faculties, they form an intention to advance in severing the afflictions of form; that they do not realize the fruit of arhatship is because transcending the realm is difficult and the activities to be generated are many. After transforming the faculties, all are realized: this means that after they have transformed and obtained keen faculties, whether severing the afflictions of form or realizing arhatship, all are obtained. Or it may mean that after stream-enterers and so forth have transformed their faculties, severing afflictions and realizing fruits are all attained, and this is not unique to the non-returner.'