摩訶止觀 3.102

3.102

隨智說三諦者，從初住去，非但說中，絕於視聽，真俗亦然。三諦玄微，唯智所照，不可示、不可思，聞者驚怪。非內非外，非難非易，非相非非相，非是世法，無有相貌，百非洞遣，四句皆亡，唯佛與佛乃能究盡；言語道斷，心行處滅。不可以凡情圖想，若一若三，皆絕情望。尚非二乘所測，何況凡夫？如乳真色，眼開乃見；徒費言語，盲終不識。如是說者，名為隨智說三諦相也，即是隨自意語。

Expounding the three truths in accord with knowledge means that from the first abode onward, not only is the middle beyond seeing and hearing, but the true and the conventional are also like this. The three truths are profound and subtle, illuminated only by knowledge; they cannot be demonstrated or conceived, and those who hear of them are startled and astonished. They are neither internal nor external, neither difficult nor easy, neither characteristic nor non-characteristic, not worldly phenomena, and devoid of appearance. The hundred negations are thoroughly dispelled, and the four propositions are entirely obliterated; only a Buddha and a Buddha can fathom them exhaustively; the path of language is cut off, and the place of mental activity is extinguished. They cannot be envisioned through ordinary sentiment; whether as one or as three, they completely surpass emotional expectations. They are not even fathomable by [practitioners of] the two vehicles, so how much less by ordinary beings? It is like the true color of milk, which is seen only when the eyes are opened; in vain are words expended, for the blind in the end do not know it. Explaining in this way is called expounding the characteristics of the three truths in accord with knowledge; this is speaking in accord with one's own intention.