金光明經文句記 2.379

2.379

二、「天台」下，明今釋常智知常。無量常智者，究竟無知方具足知，此知稱性，以全本智成佛智故。既知本性，性豈無常？古師不解，故以有知而為佛智，乃以所知是無常法。

Second, from 'Tiantai...' onward, clarifying the present explanation that eternal wisdom knows the eternal. As for 'immeasurable eternal wisdom': only when one is ultimately without knowing does one fully know; this knowing accords with the nature, because the Buddha's wisdom is formed entirely from fundamental wisdom. Since it knows the fundamental nature, how could the nature be impermanent? The ancient masters did not understand, and so took having knowledge to be the Buddha's wisdom, thereby considering what is known to be an impermanent dharma.