金剛經纂要刊定記 4.286

4.286

如凡下。明正義。斯則約有無等為四句也。謂第一是有句，第二是無句，第三是亦有亦無句，第四是非有非無句，文義兼備，故云最妙。以此四義能通實相，即是四門。

[On the passage beginning] "Like ordinary..." clarifies the correct meaning. This is taking existence, nonexistence, and so on as the four lines. That is: the first is the proposition of existence; the second is the proposition of nonexistence; the third is the proposition of both existence and nonexistence; the fourth is the proposition of neither existence nor nonexistence. Text and meaning are both complete, hence it is called "most wondrous." Because these four meanings can lead into dharmatā, they are precisely the four approaches.