大般涅槃經義記 7.83

7.83

第六難中，初先汎明因恭敬得悉是無常，次約顯法，「涅槃亦爾不名為常」，「何以故下」廣明涅槃因恭敬得，「以是義」下結成無常。

Regarding the sixth objection, first he generally clarifies that what is attained through reverence is all impermanent; next he applies it to reveal the dharma: "nirvāṇa is also like this and is not called permanent"; from "why is this?" downward extensively clarifies that nirvāṇa is attained through reverence; from "by this meaning" downward concludes that it is impermanent.