俱舍論記 25.21

25.21

「謂諸無學至容有退理」者，此即別明姓退、不退。謂諸無學，先學位中所住思等四種種姓，彼從此姓必無退理，以學、無學二道所成極堅牢故。若諸有學，先凡位中所住思等四種種姓，彼從此姓亦無退理，以世、出世二道所成極堅牢故。文中正明無學，有學義便兼明。若住無學及住學位，從退種姓後修練根，所得思等四種種姓，彼從此姓容有退理，以此種姓非二道成，不堅牢故。

Regarding 'Namely, all those who are beyond training… there is indeed reason for falling away': this specifically explains falling away and not falling away from the spiritual family. Namely, for all those beyond training (aśaikṣa), as for the four spiritual families beginning with deliberation in which they previously abided during the stage of training (śaikṣa), there is definitely no principle of their falling away from that family, because it was accomplished through the two paths of training and beyond training, and is extremely firm and stable. If for all those in training, as for the four spiritual families beginning with deliberation in which they previously abided during the worldly ordinary stage, there is also no principle of their falling away from that family, because it was accomplished through the two paths of the worldly and the supramundane, and is extremely firm and stable. The text directly explains those beyond training, and incidentally clarifies those in training as well. If, while abiding in the stage beyond training or abiding in the stage of training, one subsequently cultivates the refining of the faculties from the family of falling away, as for the four spiritual families beginning with deliberation thereby obtained, there is indeed reason for them to fall away from that family, because this spiritual family was not accomplished through two paths and is not firm and stable.