瑜伽論記 22.156

22.156

云何當觀已下，第三番解，謂由此受貪所隨眠，由隨眠故受當來苦，於現法中能生失樂受緣則生憂惱故生壞苦，如是當觀樂受為苦，云何當觀如箭至常惱壞故，此觀苦受也。非苦樂受乃至苦樂二種者，此觀捨受苦苦壞苦名苦樂二種。

From "How should one contemplate..." onward is the third round of explanation. That is, due to this feeling being accompanied by the dormancy of greed, and because of this dormancy, one undergoes future suffering; and in the present life, it can generate conditions for the loss of pleasant feeling, which then gives rise to worry and afflictive distress, thereby producing the suffering of change. In this way, one should contemplate pleasant feelings as suffering. Regarding "How should one contemplate: like an arrow... because it constantly torments and damages": this is the contemplation of painful feelings. Regarding "Neither-painful-nor-pleasant feelings... two kinds, painful and pleasant": this contemplates equanimous feelings, the suffering of suffering and the suffering of change being named the "two kinds, painful and pleasant."