金剛經纂要刊定記 5.113

5.113

三空。經徵意云：設有能信解受持，以何義故得為希有？釋意云：以無我等相故，此則我空也。

The three emptinesses. The intent of the sūtra's query is: supposing there are those who can believe, understand, and uphold it, on what basis are they considered rare? The intent of the explanation is: because they are free from the marks of a self and so forth; this is the emptiness of self.