瑜伽論記 8.145

8.145

法性行中，云謂即所有變異無常等者，此中意如現在樂受正受樂時未變異無常，以變異等前三種無常行故，觀今樂受於當來世必當無常故，如是通達如是樂受於當來世必定無常，故名法性無常。

In the aspect of nature (dharmatā), regarding "namely, that which is the impermanence of alteration..." and so forth: the meaning here is that when a present pleasant feeling is currently being experienced as pleasure, it has not yet undergone the impermanence of alteration; but by means of the three prior aspects of impermanence, such as alteration, one contemplates that this present pleasant feeling will certainly be impermanent in the future. Because one thoroughly penetrates that this pleasant feeling will certainly be impermanent in the future in this way, it is called the impermanence of nature.