摩訶止觀 4.34

4.34

次「觀因緣生心即中」者，觀於心性畢竟寂滅，心本非空亦復非假。非假故非世間；非空故非出世間。非賢聖法，非凡夫法；二邊寂靜，名為「心性」。能如是觀，名為「上定」。心在此定即「首楞嚴」。本寂不動，雙照二諦，現諸威儀，隨如是定無不具足。如是觀心，防止二邊無明諸惡，善順中道一實之理；防邊論止，順邊論觀，此名「即中而持兩戒」也。

Next, regarding "contemplating that the mind born of conditioned arising is identical to the middle": one contemplates the mind-nature as ultimately tranquil and extinct; the mind is originally neither empty nor provisional. Because it is not provisional, it is not worldly; because it is not empty, it is not world-transcending. It is neither the phenomena of the worthy and holy, nor the phenomena of ordinary beings; the two extremes being tranquil is called the "mind-nature." Being able to contemplate in this way is called the "supreme concentration." When the mind resides in this concentration, it is the Śūraṅgama [samādhi]. Originally tranquil and unmoving, it doubly illuminates the two truths and manifests all deportments; in accord with such a concentration, none are not fully possessed. Contemplating the mind in this way wards off the various evils of ignorance concerning the two extremes and accords well with the principle of the one reality of the middle way. Discussing calming in terms of warding off, and contemplation in terms of according, this is called "upholding two kinds of precepts by being identical to the middle."