釋禪波羅蜜次第法門 7.48

7.48

When the practitioner has regulated the breath continuously and attends to the breath with single-mindedness, when the breath enters, they know it enters from the tip of the nose down to the navel; when it exits, they know it exits from the navel up to the nose. Illuminating the breath with single-mindedness in this way, attending to it without distraction, at that time they know the coarse and subtle characteristics of the breath. As for coarse, knowing wind and panting breath is coarse; as for subtle, knowing the breath aspect is subtle. If the in-breath is coarse, they regulate it to make it subtle; this is called knowing coarse and subtle characteristics. It is just like a gatekeeper who knows the people entering and exiting the gate, and also knows good people and bad people: knowing them to be good, he lets them in; knowing them to be bad, he turns them away.