俱舍論疏 13.7

13.7

論「以諸有情至二事俱妙」，答。業類不同，雜業生人感內身形常流不淨，感外香等能對治彼；淨業生天，二事皆淨。

Treatise: "Because for sentient beings […] both things are excellent." This is the answer. The classes of karma are different: mixed karma brings birth as a human, resulting in an internal physical form that constantly discharges impurity, and resulting in external scents and the like that can counteract it; pure karma brings birth in the heavens, where both things are pure.