摩訶止觀 7.3

7.3

Fifth, discerning passage and obstruction: this is also called 'knowing gain and loss,' and 'knowing what are letters and non-letters.' Through pervasively destroying phenomena as described above, one should unobstructed pass through and enter into non-arising; if one does not enter, one must examine gain and loss, for one is certainly stuck in right and wrong and cannot form a one-sided understanding. How so? If, like non-Buddhists, one craves and clings to the wisdom of contemplating emptiness, one should use the four phrases to pervasively destroy it, where that which destroys is like what is destroyed, so that all obstructions may gain passage. If one does not cling to the wisdom of contemplating emptiness, then that which destroys is not like what is destroyed: one only destroys obstructions and preserves passage. This is like removing a cataract while preserving the eye, or defeating bandits while protecting the general. If so, then like a great guide, one skillfully knows passage and obstruction, and can lead the multitude to cross the five hundred yojanas.