釋禪波羅蜜次第法門 7.55

7.55

Third, knowing whether the breath is long or short: this corresponds to the desire-realm absorption. If one realizes the desire-realm absorption, that absorption ought to be clear and pure without perceiving or knowing any characteristics in the breath at all. Now, here, when one first attains absorption, one immediately perceives the characteristics of long and short in the breath. How is this perceived? When the mind is settled in absorption, one perceives that the inhalation is long and the exhalation is short. Why is this? Since the mind abides quietly within, the breath enters following the mind; thus, entering, it is known to be long. Since the mind does not condition external objects, exiting, it is known to be short.