摩訶止觀 7.16

7.16

若一心三觀法相，即破竪中之通塞；三觀一心破橫中之通塞。空即三觀，故破步涉山壁，三百之通塞；假即三觀，破乘馬四百之通塞；中即三觀，破神通之通塞。良以一心能即空、假、中者，一切山河石壁、眾魔群道皆如虛空。一心三觀遊之無礙，終不去下陵高，避山從谷。觸處諸塞皆通無礙，能過五百由旬到於寶所。是名為「通」。通本對塞，既觸處如空，則無復有塞；無塞則無通。

If the characteristics of dharmas are the three contemplations in a single mind, they immediately break the obstruction and opening within the vertical; the single mind with three contemplations breaks the obstruction and opening within the horizontal. Emptiness is precisely the three contemplations, so it breaks the obstruction and opening of the three hundred—the walking on foot amidst mountains and walls; provisionality is precisely the three contemplations, breaking the obstruction and opening of the four hundred—the riding of a horse; the middle is precisely the three contemplations, breaking the obstruction and opening of supernormal powers. Because a single mind can be precisely empty, provisional, and the middle, all mountains, rivers, stone walls, the hosts of Māra, and the various paths are all like empty space. The three contemplations in a single mind roam through them without hindrance, never descending to what is low or climbing what is high, avoiding mountains and following valleys. All obstructions encountered are open and unimpeded, able to surpass the five hundred yojanas and reach the jewel repository. This is called "opening." Opening originally stands opposite obstruction; since all places encountered are like empty space, there is no longer any obstruction; without obstruction, there is no opening.