成唯識論掌中樞要 2.113

2.113

三受之中何故但說苦、樂為名，不標憂、喜？以苦對樂，俱通三性；以憂對喜，理則不然。以寬攝狹，但名苦、樂。又苦與樂行相猛利，以明攝暗，憂、喜不等。又苦與樂皆是異熟，並有異熟；憂之與喜不能具足。又具果因攝不具故。又有異釋：以苦對樂，俱通六識；以憂對喜，唯在意中。又說苦、樂厭、欣行增；憂、喜不然，故標苦、樂。又苦對樂，俱通無學；以憂對喜，離欲便除，故說苦、樂。又以苦對樂，俱上地捨；以憂對喜，皆先下地除，故說苦、樂。

Among the three feelings, why are only pain and pleasure spoken of by name, without designating grief and joy? Because comparing pain to pleasure, both encompass the three moral natures; comparing grief to joy, the principle is not so. Using the broad to subsume the narrow, only pain and pleasure are named. Furthermore, the active aspects of pain and pleasure are fierce and sharp; using the clear to subsume the obscure, grief and joy are not equivalent. Furthermore, pain and pleasure are both maturation and have maturation; grief and joy cannot possess [this] completely. Furthermore, that which possesses cause and fruition subsumes that which is incomplete. There is also another explanation: comparing pain to pleasure, both encompass the six consciousnesses; comparing grief to joy, they are exclusively in the manas. Furthermore, it is said that in pain and pleasure, the activities of revulsion and delight are pronounced; with grief and joy it is not so, hence pain and pleasure are designated. Furthermore, comparing pain to pleasure, both encompass the stage beyond study; comparing grief to joy, they are abandoned upon detaching from desire, hence pain and pleasure are stated. Furthermore, comparing pain to pleasure, both are renounced in the higher stages; comparing grief to joy, both are abandoned in the lower stages first, hence pain and pleasure are stated.