俱舍論記 3.34

3.34

「手足不應至建立為根」者，此破手、足。手於執、足於行，此執與行離手、足外無異性故。謂即手、足從此至彼名異處，舉、下、屈、申名異相，由此差別生時名執名行，離手、足外無別執行。又離手、足亦有執行，猶如蛇等諸腹行類，雖無有足而亦能行，雖無有手亦能執縛。是故手、足不可於彼執、行建立為根。若固執者亦有由腹，應立腹根。

Regarding "Hands and feet should not be... established as faculties": this refutes the hands and feet. Hands are for grasping, and feet are for walking; this grasping and walking have no nature distinct from the hands and feet themselves. That is to say, the hands and feet going from here to there is called distinct positions; raising, lowering, bending, and extending are called distinct characteristics. When these distinctions arise, they are called grasping and walking; apart from the hands and feet, there is no distinct grasping or walking. Furthermore, even apart from hands and feet, there are grasping and walking: like snakes and other belly-crawling creatures, who can walk though they have no feet, and can grasp and bind though they have no hands. Therefore, hands and feet cannot be established as faculties for that grasping and walking. If one obstinately clings [to this position], then since [walking] also depends on the belly, one ought to establish a belly-faculty.