四教義 3.5

3.5

Third, explaining the four gates of the distinctive teaching: If one uses the phrase 'it is also called conventional designation' from the Madhyamaka-kārikā to distinguish the four gates, these are the four gates of the distinctive teaching; the four phrases from the Dà zhìdù lùn may also be used. The import of these four gates of the distinctive teaching directly emerges from the Mahāparinirvāṇa-sūtra, though it is mostly expounded in scattered places; explaining the four-phrase metaphors in terms of milk constitutes the four gates of the distinctive teaching. If it explains that Buddha-nature is like milk having the nature of curd, a stone having the nature of gold, or the jewel on the wrestler's forehead, this is the gate of existence. If it explains that a stone has no nature of gold, milk has no nature of curd, sentient beings' Buddha-nature is like empty space, the great nirvāṇa is empty, or the city of Kapilavastu is empty, this is the gate of emptiness. The Nirvāṇa Sūtra also says: 'Regarding Buddha-nature being both existent and non-existent: how is it existent? Because all sentient beings possess mind. How is it non-existent? Because it is seen through skillful expedients.' Moreover, just as in milk there is both the nature of curd and no nature of curd, this is the gate of both existence and non-existence. If it explains that Buddha-nature is identical to the middle way because the hundred negations are mutually eliminated—as the sūtra's metaphor says: 'In milk there is neither the nature of curd nor no nature of curd'—this is the gate of neither emptiness nor existence. The bodhisattvas of the distinctive teaching distinctively receive the teaching of these four gates, and through it they see Buddha-nature and abide in great nirvāṇa; therefore the teachings of these four phrases are the four gates of the distinctive teaching. Now, for the time being, we distinguish the characteristics of the four gates of the distinctive teaching according to the text of the Nirvāṇa Sūtra, yet this sūtra text may perhaps also be the four gates of the perfect teaching; when we come below to the four gates of the perfect teaching, we shall naturally analyze their similarities and differences. Question: If the four gates of the distinctive teaching only come from the Nirvāṇa Sūtra, then why do the previous Mahāyāna sūtras lack the four gates of the distinctive teaching? Answer: The Mahāparinirvāṇa-sūtra is a sūtra that explains the previous teachings; how could those earlier Mahāyāna sūtras lack the four gates of the distinctive teaching? To cite the sūtra passages in full would be too cumbersome.