金剛經纂要刊定記 5.122

5.122

大因。經徵意云：以何義故，聞而不驚等得為希有耶？釋意云：以此法門於諸波羅蜜中是第一波羅蜜故。然此波羅蜜，若約勝義則不可言，故言非第一等。今所說者約世諦說，為勝之義不亦然乎，故云是名等。

The great cause. The intent of the sūtra's query is: on what basis is hearing without alarm and so forth considered rare? The intent of the explanation is: because this Dharma-door is the foremost pāramitā among all pāramitās. Yet this pāramitā, if considered according to paramārtha, cannot be spoken of, hence it says "is not the foremost" and so forth. What is currently spoken is said according to conventional truth; is not the meaning of its superiority precisely so? Hence it says "is called..." and so forth.