摩訶止觀 3.72

3.72

Regarding the 'contemplation of the supreme meaning of the middle way': the former contemplation made provisionality empty, which empties saṃsāra; the latter contemplation made emptiness empty, which empties nirvāṇa. Simultaneously shutting off both extremes is called the 'contemplation of dual emptiness', which serves as the path of expedients to attain union with the middle way. Therefore it is said: 'Thought after thought ceases, flowing into the ocean of sarvajñā.' Furthermore, the first contemplation employs emptiness, and the latter contemplation employs the provisional; this is the expedient of dual preservation. When entering the middle way, one is able to illuminate both truths simultaneously. Therefore a sūtra says: 'If the mind is in concentration, it can know the characteristics of the arising and perishing of phenomena in the world.' That the preceding two contemplations serve as two kinds of expedients has this meaning.