大般涅槃經義記 6.284

6.284

釋中，先徵何故言密，下對釋之。於中六番，前四對人，後二就法。就前四中，明其為者汎為一切，阿闍世者偏論阿闍世王般類。四番何別？初言為者，汎為一切凡夫眾生，言阿闍者，舉阿闍世般取一切五逆眾生。

In the explanation, he first queries why they are called secret, and below explains in response. Within this there are six rounds: the first four deal with persons, and the latter two concern dharmas. In the first four, explaining that "acting for" refers broadly to everyone, while "Ajātaśatru" refers specifically to the kind of beings like King Ajātaśatru. What is the distinction among the four rounds? In the first, "for" refers broadly to all ordinary beings; "Ajāta" takes King Ajātaśatru to subsume all beings of the five cardinal sins.