金剛經纂要刊定記 3.73

3.73

謂護下。指經。便是釋。意謂以小付大，囑大化小，展轉如是寧有斷絕，如人父母付囑子孫云云。此是空生之本意，故以此事讚佛，引起問端也。

"Regarding 'protecting'..." points to the sūtra. This is the explanation. It means entrusting the Great [Vehicle] to the Small, and charging the Great to transform the Small; being transmitted turn by turn in this manner, how could there ever be interruption? Just as when human parents entrust matters to their children and grandchildren, and so on. This was Subhūti's original intention; therefore he praised the Buddha with this matter, giving rise to the opening of the inquiry.