金剛般若波羅蜜經註解 1.39

1.39

護念付囑，即希有事也。佛德之大，無過度生，然雖注意於般若度生，必待請問，故善現覩相知意，即首稱歎希有而後請問也。

Protecting, keeping in mind, and entrusting are precisely the 'rare' things. Of the greatness of the Buddha's virtue, nothing surpasses saving sentient beings; yet, although his intention was set upon saving sentient beings through prajñā, he had to wait for a formal request. Therefore Subhūti, seeing his countenance and knowing his intention, first praised him as rare and then made his request.