俱舍論頌疏論本 28.76

28.76

The explanation says: As for the first two lines, the arising of the samāpattis relies on their own or lower bodies; relying on the body of an upper stage, there is no possibility of arising the lower: first, because when in an upper stage, giving rise to a lower stage has no utility; second, because one's own stage has superior absorption; third, because the power of the lower absorption is inferior (the above applies generally to both pure and undefiled); fourth, because one has fallen away from and abandoned the lower stage; fifth, because the phenomena of the lower stage are to be reviled and disliked (these two apply solely to the pure samāpatti).