成唯識論了義燈 5.39

5.39

問：何故不言憂、喜、捨三以攝苦、樂？答：憂、喜有異熟，體非是異熟。苦、樂有異熟，又體是異熟。又苦、樂通三性，憂非染、無記。又憂離欲捨，餘非離欲捨。苦、樂體寬，舉攝憂、喜。

Question: Why not speak of the three—grief, joy, and equanimity—to subsume pain and pleasure? Answer: Grief and joy have ripening [effects], but their substance is not ripening. Pain and pleasure have ripening [effects], and their substance is also ripening. Furthermore, pain and pleasure extend through the three moral natures, whereas grief is not defiled [in the upper realms] or non-defined. Furthermore, grief is abandoned upon detachment from desire, while the others are not abandoned upon detachment from desire. The substance of pain and pleasure is broader; by adducing them, grief and joy are subsumed.