俱舍論疏 11.153

11.153

論「少光以上至所壽劫量」，明上下天劫大、中不同。初定三天以半大劫為其一劫，二定已上以大全劫為一劫。詳其上壽量增減及身量增減，欲天、色天及無色天，色天初定以半劫為劫，及中間靜慮身量等不同者，皆是生死法爾因果。如此，不可細求所以多眼、三眼、二眼、一眼，及無足、多足等也。

The Commentary states, "From 'From Parīttābha upward' up to 'the kalpa measures of their life span,'" explaining that the higher and lower gods differ in whether their kalpas are great or medium. The three heavens of the first dhyāna take half a mahākalpa as one kalpa; from the second dhyāna upward, they take a full mahākalpa as one kalpa. When carefully examining the increases and decreases of the above lifespans and bodily measurements among the gods of desire, form, and formless realms—where in the first dhyāna of the form realm half a kalpa counts as a kalpa, as well as the differences in bodily measurement in the intermediate dhyāna and so on—these are all natural cause and effect within saṃsāra. Like this, one cannot excessively scrutinize the reason why there are many eyes, three eyes, two eyes, one eye, or being footless, having many feet, and so forth.