俱舍論記 22.98

22.98

「若先無苦至生於苦覺」者，經部等問。若先無苦，於最後時何為歘然生於苦覺？良由初位苦微不覺，後漸苦增，方能覺苦。

Regarding "If initially there is no suffering ... how could the awareness of suffering arise?": The Sautrāntikas and others ask: If initially there is no suffering, why in the final state should an awareness of suffering suddenly arise? It is precisely because in the initial state suffering is subtle and unperceived, and subsequently suffering gradually increases, that one is only then able to perceive suffering.