大般涅槃經義記 3.142

3.142

上勸供養，自下第二教其撿驗。前已驗竟，何勞重驗？釋言：前者魔化為依，邪來亂正，故教撿驗。今此四依亦同破戒，以正濫邪，故復須驗。迦葉先請，如來次教，「迦葉」下復領解讚嘆。請中，初言「眾僧之中有四種人」，法說明濫。內熟外生、外熟內生、內外俱生、內外俱熟，是四種人「如菴羅果」喻說明濫。「破戒、持戒，云何可識」，請佛教示。

The above exhorted making offerings; next, the second part instructs in scrutinizing and verifying. Since they have already been verified before, why bother to verify them again? The explanation says: previously, māras manifested as reliances, heterodoxy coming to confound orthodoxy, hence he instructed in scrutinizing and verifying. Now, these four reliances likewise appear identical to precept-breakers, confusing the heterodox with the orthodox, hence they must again be verified. Kāśyapa first requests, the Tathāgata next instructs, and from 'Kāśyapa' onward again understands, receives, and praises. In the request, it first states: 'within the Saṅgha there are four kinds of persons,' doctrinally explaining the confusion. Ripe inside and raw outside, ripe outside and raw inside, both raw inside and outside, both ripe inside and outside: these four kinds of persons are 'like mango fruits,' metaphorically explaining the confusion. 'Precept-breakers and precept-holders: how can they be recognized?' requests the Buddha's instruction.