佛祖統紀 3.134

3.134

祕密文證此有二義。一者義蘊經論。妙玄引涅槃經。迦葉菩薩設三十六問。如來讚云。我初成佛亦有菩薩來問斯義。所問句義功德亦皆如是（此佛親宣）又般若經。諸天子唱言。我見閻浮提第二法輪轉。今轉似初轉（此諸天敘出）二者名出龍樹。大論釋般若經云。諸佛法輪有二種。一者顯。二者密。初轉聲聞見八萬億人（此顯露不定教）諸菩薩見無量阿僧祇人得無生忍（此祕密不定教）。

Textual evidence for the Secret [Teaching]: This has two aspects. First, the meaning is contained in the sutras and treatises. The Miaoxuan cites the Mahāparinirvāṇa-sūtra, where Bodhisattva Kāśyapa poses thirty-six questions, and the Tathāgata praises him, saying: 'When I first attained Buddhahood, there was also a bodhisattva who came to inquire about this matter; the phrasing, meaning, and merits of his questions were all entirely like this.' (This was personally proclaimed by the Buddha.) Furthermore, in the Prajñāpāramitā-sūtras, the devaputras proclaim aloud: 'We see the second turning of the Dharma wheel in Jambudvīpa; the turning now resembles the initial turning.' (This was recounted by the devas.) Second, the name originates with Nāgārjuna. The Dazhidulun, explaining the Prajñāpāramitā-sūtras, says: 'The Dharma wheels of the Buddhas are of two kinds: first, the manifest; second, the secret. At the initial turning, the śrāvakas saw eighty trillion persons [gain the fruit] (this is the manifest indeterminate teaching); the bodhisattvas saw immeasurable asaṃkhyeya persons attain the patience of non-arising' (this is the secret indeterminate teaching).