俱舍論記 28.107

28.107

「謂別有喜至其體各異」者，外人引餘部答。或餘部言，顯上坐部。謂別有喜，是心所法，非是喜受。前三定樂皆是喜受，故喜、喜受其體各異。

Regarding the passage "Meaning that there is a distinct joy... their entities are distinct from each other": The opponent cites other schools in reply. Or, the phrase "other schools" indicates the Sthaviravāda. It means there is a distinct joy, which is a mental factor and not the sensation of joy. The pleasures of the first three absorptions are all sensations of joy; therefore, joy and the sensation of joy are distinct in entity from each other.