維摩經玄疏 6.43

6.43

First, the two truths in which the middle way buddha-nature is combined with the ultimate truth are still the two truths of the shared teaching. They are not shared only with the two vehicles, but are also shared with the distinctive and shared with the perfect. As for what is called combining the middle way with the ultimate to constitute paramārtha-satya, the Nirvāṇa Sūtra states: "What is called buddha-nature is precisely the emptiness of the supreme meaning. The emptiness of the supreme meaning is called wisdom. The wise see emptiness and also non-emptiness." Non-emptiness is precisely the middle way, and emptiness is precisely the ultimate truth. Hence we know that the middle way buddha-nature combined with the ultimate truth constitutes paramārtha-satya. There are also three kinds of two truths here, which can be known by analogy with the preceding.