釋禪波羅蜜次第法門 7.48

7.48

行者既調息綿綿，一心依隨於息，息若入時，知從鼻端入至臍；若出時，知從臍出至鼻。如是一心照息，依隨不亂，爾時知息麁細之相。麁者，知風喘氣為麁；細者，知息相為細。若入息麁時，即調之令細，是名知麁細相。譬如守門之人，知門人出入，亦知好人、惡人，知好則進，知惡則遮。

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.