俱舍論記 22.166

22.166

「唯人趣生至況餘界生」者，釋人生。又《婆沙》云「問：何處起此不淨觀耶？答：唯人三洲能初現起，天中無有青瘀等相，故六欲天唯能後起。有說：初後皆唯人趣，六欲天中無青瘀等不淨相故都不現起。」《俱舍》同《婆沙》後師。若據初起，或同《婆沙》前師。《正理》同《婆沙》前師。

The words 'Arising only in the human destiny ... how much less for those born in other realms' explain arising in humans. Furthermore, the Mahāvibhāṣā says: 'Question: Where does this contemplation of impurity arise? Answer: It can initially become manifest only in the three continents of humans; among devas there are no signs of lividity and so forth, so in the six heavens of the desire realm it can only arise subsequently. Some say: Both initially and subsequently, it is only in the human destiny; because in the six heavens of the desire realm there are no impure signs such as lividity, it does not become manifest at all.' The Kośa agrees with the latter master of the Mahāvibhāṣā. If based on initial arising, it perhaps agrees with the former master of the Mahāvibhāṣā. The Nyāyānusāra agrees with the former master of the Mahāvibhāṣā.