俱舍論記 25.23

25.23

「又亦無退至應是進非退」者，就四果中明退果義。雖五種姓皆可退果，又亦無退先所得果。四果之中但先得者必定不退。若預流果得必先得，一來、不還超越證者亦是先得，後所得果容有退義。若以第一果為先，即以二、三、四果為後。若以第二果為先，即以三、四果為後。若以第三果為先，即以第四果為後。是故定無退預流果，以預流果必先得故，此中偏說。一來、不還以不定故，故不別舉。應知預流唯先非後，羅漢唯後非先，一來、不還俱通先、後。由此無退先得果義、退後果義，所以應果退法有三：一增進根、二退住學、三住自位而般涅槃。但言退住學位，不言退住異生，以此明知非退初果。思法有四，三如前說，更加一種退住退姓，餘三如次。護法有五，四如前說，更加一種退住思姓。安住法有六，五如前說，更加一種退住護法姓。堪達法有七，六如前說，更加一種退住安住姓。思法等四退住學位時，還住先退姓，非餘思等四。若異此者，先時學位是退種姓。今退住學思等四姓，得勝種姓故，應是進非退。

Regarding 'Moreover, there is also no falling away… it would be an advance and not a falling away': this explains the meaning of falling away from the fruit with respect to the four fruits. Although all five spiritual families may fall away from the fruit, moreover, there is also no falling away from the fruit initially obtained. Among the four fruits, whichever is obtained first is definitely not fallen away from. The fruit of stream-entry (srotāpanna), if obtained, is necessarily obtained first; for those who realize once-return (sakṛdāgāmin) or non-return (anāgāmin) by leaping over, these are also obtained first; the fruits obtained later admit of falling away. If one takes the first fruit as the initial one, then the second, third, and fourth fruits are subsequent. If one takes the second fruit as the initial one, then the third and fourth fruits are subsequent. If one takes the third fruit as the initial one, then the fourth fruit is subsequent. Therefore, there is definitely no falling away from the fruit of stream-entry, because the fruit of stream-entry is necessarily obtained first; here it is stated specifically. Because once-return and non-return are not fixed, they are not separately cited. It should be known that stream-entry is only initial and not subsequent; arhatship is only subsequent and not initial; once-return and non-return both extend to the initial and the subsequent. Because of this principle that there is no falling away from the initially obtained fruit and that one falls away from subsequent fruits, the dharma of falling away in the fruit of arhatship has three [possibilities]: first, progressing in faculties; second, falling away to abide in training; third, entering parinirvāṇa while abiding in one's own level. It only says 'falling away to abide in the stage of training' and does not say 'falling away to abide as an ordinary person'; through this it is clearly known that one does not fall away from the first fruit. The deliberation-dharma has four [possibilities]: three are as previously stated, with the addition of one kind, namely falling away to abide in the family of falling away; the remaining three follow in sequence. The preservation-dharma has five: four are as previously stated, with the addition of one kind, namely falling away to abide in the family of deliberation. The abiding-dharma has six: five are as previously stated, with the addition of one kind, namely falling away to abide in the family of preservation. The capable of penetration-dharma has seven: six are as previously stated, with the addition of one kind, namely falling away to abide in the family of abiding. When the four beginning with the deliberation-dharma fall away to abide in the stage of training, they return to abide in their prior family of falling away, and not in the remaining four beginning with deliberation. If it were otherwise, their previous stage of training was the family of falling away; if they now fell away to abide in training in the four families beginning with deliberation, they would be obtaining a superior spiritual family, and so it would be an advance and not a falling away.