摩訶止觀 4.186

4.186

復次，約三觀各各調者：初觀止身息心為急滑沈，次觀身息心為寬澁浮。若能中適，即成方便，得入真諦也。第二觀止身息心為急滑沈，觀身息心為寬澁浮。能止觀中適，則成方便，發道種智，見俗諦理（云云）。中道止身息心為急滑沈，觀身息心為寬澁浮。若能中適，止觀從容，即成方便，得入中道見實相理也。行者善調三事，令託聖胎。如即行，心未有所屬，應當勤心和會方便、智度父母，託於聖胎。豈可託地獄三途、人天之胎耶？

Furthermore, regarding regulating each of the three contemplations individually: in the first contemplation, calming body, breath, and mind is taut, smooth, and sunken; contemplating body, breath, and mind is loose, rough, and agitated. If they can be balanced and moderate, this forms an expedient means and one is able to enter the true truth. In the second contemplation, calming body, breath, and mind is taut, smooth, and sunken; contemplating body, breath, and mind is loose, rough, and agitated. If calming and contemplation can be balanced and moderate, this forms an expedient means, gives rise to the knowledge of the aspects of the path, and sees the principle of conventional truth (and so forth). In the middle way, calming body, breath, and mind is taut, smooth, and sunken; contemplating body, breath, and mind is loose, rough, and agitated. If they can be balanced and moderate, and calming and contemplation are leisurely, this forms an expedient means, and one is able to enter the middle way and see the principle of true reality. Practitioners who skillfully regulate the three matters cause themselves to be conceived in the noble embryo. If in immediate practice the mind has not yet found its allegiance, one should diligently harmonize the expedients and the parents of prajñāpāramitā, taking conception in the noble embryo. How could one be conceived in the womb of hell, the three destinies, or of humans and devas?