妙法蓮華經玄義 9.85

9.85

二、依經修行者，前信、法兩行，意通時寬，或經劫數，譬如長圍。若依諸經別明行法，剋日制時，喻如苦攻。若隨事行行，行則無體；若隨理行行，令此空慧與行相應，能破無量障道罪，能得無生忍者，此行有體。諸經別行乃多，略言其四：謂常行行、常坐行、半行半坐行、非行非坐行。諸行各有事相方法，勤身苦策，悉用實相正觀為體。念念無間，清淨如空，具論觀意，如《止觀》中說。

Second, regarding cultivating practice relying on the sūtras: the two previous practices of faith and dharma have a broad scope and a wide timeframe, perhaps extending over kalpas, which is like a prolonged siege. If one relies on the specific methods of practice clarified in various sūtras, fixing the days and regulating the hours, this is likened to an intense assault. If one pursues practices along with external phenomena, the practice lacks substance; if one pursues practices along with principle, causing this empty wisdom to accord with practice, so that it can destroy measureless transgressions that obstruct the path and attain the patience of the unproduced nature of dharmas, then this practice has substance. Specific practices in the sūtras are many, but to state them briefly there are four: the practice of constant walking, the practice of constant sitting, the practice of half walking and half sitting, and the practice of neither walking nor sitting. Each of these practices has its phenomenal methods, with diligent physical exertion, yet all take the correct contemplation of the real mark as their substance. Kept moment to moment without interruption, pure as empty space; the full explanation of the intent of contemplation is as explained in the Mohe Zhiguan.