大般涅槃經義記 7.39

7.39

三就生相明常、無常，當知此生亦常、無常，如下文說。於事分齊，色等法邊恒有此生，故名為常。於法分齊，此之生相運運起盡，一謝往者更不重現，故曰無常。

Third is clarifying permanence and impermanence with respect to the mark of arising. One should know that this arising is also permanent and impermanent, as explained in the text below. In terms of the scope of phenomena, alongside dharmas such as matter, there is constantly this arising; hence it is called permanent. In terms of the scope of dharmas, this mark of arising rises and falls moment by moment; once it has passed away, it never appears again; hence it is called impermanent.