大般涅槃經義記 7.246

7.246

四「而是涅槃不從因」下顯前第一明非聲果，不從因生故非聲果。上來廣辯，「以是義」下結成不定。

Fourth, the passage from "Yet this nirvāṇa does not [arise] from causes" onward reveals the first [clause] above, clarifying that it is not the fruit of sound; because it does not arise from causes, it is not the fruit of sound. The above broadly distinguished it, and the passage from "By this meaning" onward concludes that it is indeterminate.