佛祖統紀 3.135

3.135

祕密不傳。文句云。祕密者。隱而不傳。記云。降佛七還非所述。故尚非阿難能受。豈弘教者所量。阿難非不傳祕。赴機之密非所傳耳。故祕密不用。全是顯露。是故傳祕密。名傳顯。諸師皆云。上聖赴機之密。互不相知故不可傳。若涅槃中。如來親宣般若。故天子唱出。皆結集為文。還成顯露。故可傳耳。

The Secret [Teaching] is not transmitted: The Wenju says: 'What is secret is hidden and not transmitted.' The Ji says: 'Even descending below the Buddha's seven [paces] was not what was recounted; thus, it was not something even Ānanda could receive, so how could it be measured by those who propagate the teaching?' It is not that Ānanda did not transmit the secret; rather, the secret of responding to individual capacities is simply not something that can be transmitted. Therefore, the secret is not used—it is entirely manifest. For this reason, transmitting the secret is called transmitting the manifest. The various masters all say: 'The secret of the supreme sage responding to capacities cannot be transmitted because [the recipients] are mutually unaware. But as in the Nirvāṇa, the Tathāgata personally proclaimed it, and in the Prajñā, the devaputras proclaimed it aloud, both being compiled into texts and returning to being manifest; therefore, they can be transmitted.'