俱舍論記 22.71

22.71

「苦易脫中至定無實樂」者，釋第二章。苦易脫中，於其輕苦愚夫謂樂，如荷重擔暫易肩等，於初輕苦妄謂為樂，故受唯苦定無實樂。若依經部，三受皆具三苦。謂三受實是苦受，故皆是苦苦。三受相續斷位變壞故，皆是即壞即苦。三受念念生滅故，皆是即行即苦。

As for "In the shifting of suffering... definitely no real pleasure": this explains the second section. In the shifting of suffering, the foolish ordinary person deems its light suffering to be pleasure, just as when carrying a heavy burden one temporarily shifts it to the other shoulder and the like, falsely deeming the initial light suffering to be pleasure; therefore, feeling is solely suffering, and there is definitely no real pleasure. If one follows the Sautrāntikas, all three feelings possess the three sufferings: because the three feelings are in reality painful feelings, they are all the suffering of suffering; because the three feelings undergo deterioration at the stage where their continuum is broken, they are all suffering that is deterioration itself; because the three feelings arise and perish moment by moment, they are all suffering that is conditioned existence itself.