金光明經文句記 3.64

3.64

初、據所聞釋信相解。言本迹者，體本、用迹也。聞壽無量，解迹用能常，非長之長也，乃知迹用能短，非短而短。定八十之疑，自茲而去也。深心者，悟於報法高深之體也。此之本體，妙絕於量及以無量。

First, explaining Ruciraketu's understanding based on what was heard. 'Fundamental and trace' means that the substance is fundamental and the function is trace. Hearing of the immeasurable lifespan, he understood that the trace function can be permanent, a length that is not long; he also knew that the trace function can be short, a shortness that is not short. His fixed doubt concerning eighty [years] departed from this point. 'Deep mind' means awakening to the lofty and deep substance of the retribution Dharma. This fundamental substance is wondrously beyond both measure and immeasurability.