摩訶止觀 3.10

3.10

觀達義者，觀智通達，契會真如。《瑞應》云：「息心達本源，故號為沙門。」《大論》云：「清淨心常一，則能見般若。」此就能觀得名，故立觀達觀也。

As for the meaning of penetrating contemplation: contemplative wisdom penetrates through, tallying and uniting with true suchness. The Ruiying says: 'Ceasing the mind and penetrating the original source, one is therefore called a śramaṇa.' The Mahāprajñāpāramitopadeśa says: 'When the pure mind is constantly unified, one is able to see prajñā.' This receives its name from that which is able to contemplate; therefore it establishes the contemplation of penetrating contemplation.