金光明經文句記 2.168

2.168

初、明應物有三，初身、二壽、三量，皆如谷響大小隨聲。是故此三悉云應同。

First, explaining that there are three in responding to beings: first, body; second, lifespan; third, measure; all are like an echo in a valley, their size following the sound. Therefore, these three are all called corresponding responses.