俱舍論記 7.98

7.98

「學心從四至及無學一」者，明學、無學與諸心相生，非三界染互相違故，非諸無覆無明利故。所以無學不生學者，彼非果故。

Regarding "The mind of the trainee [arises] from four ... and one of the non-trainee": this explains the mutual arising of the minds of the trainee and the non-trainee with the various [other] minds. This is because they are not [compatible with] defilement of the three realms, being mutually opposed to it; nor are they [compatible with] the non-defiled [unspecified minds], because they are lucid and sharp. The reason why the mind of the non-trainee does not produce that of the trainee is that [the trainee's mind] is not its fruit.