大般涅槃經義記 3.313

3.313

合中，「佛性亦復如是」合前伏藏。「一切論者及天、魔」等合上有人，一切沙門、婆羅門等名為論者，此等皆是求性之人，所以舉之。「所不能壞」合至金剛，「不能穿徹五陰相」等却合斲地，磐石、砂礫直過無難，先舉其法，後以喻帖。「性如金剛不可沮壞」合夫金剛力斧不壞。

In the application [of the analogy], "buddha-nature is also like this" applies to the buried treasure above. "All disputants, as well as devas, Māra," and so forth applies to the person above; all śramaṇas, brāhmaṇas, and so forth are called disputants; these are all people who seek the nature, which is why they are adduced. "That which cannot be broken" applies to reaching diamond. "Cannot pierce through the characteristics of the five aggregates" and so forth applies back to digging the earth and passing straight through boulders, sand, and gravel without difficulty, first adducing the dharma, and then attaching the analogy. "The nature is like diamond and cannot be destroyed" applies to the diamond which cannot be broken by a powerful axe.