金剛經纂要刊定記 4.177

4.177

福德門。經意云：信經之人得無量福，如來於彼咸悉知見。如是無量福者，指信經福。同前不住施福，十方虛空不可思量也。

The approach of merit. The sūtra's meaning is: the person who believes in the sūtra attains immeasurable merit, and the Tathāgata fully knows and sees them. "Such immeasurable merit" points to the merit of believing in the sūtra. Like the earlier merit of giving without abiding, it is inconceivable like the empty space of the ten directions.