俱舍論頌疏論本 2.100

2.100

頌曰「身識自下地」，自者，生欲界初禪也，謂欲界初禪，身識望於身觸皆同地故，名為自也。下者，生上三定，借初禪識，覺上地觸，此即身識望於身觸，在下地也。

The verse says: 'Body-consciousness is of its own and lower levels.' 'Own' refers to being born in the desire realm or the first dhyāna: that is, in the desire realm and first dhyāna, body-consciousness in relation to the body and tangible objects is entirely of the same level, hence it is called 'own'. 'Lower' means that when born in the upper three dhyānas, one borrows the consciousness of the first dhyāna to feel the tangible objects of the higher levels; in this case, the body-consciousness, in relation to the body and tangible objects, is on a lower level.