釋禪波羅蜜次第法門 7.55

7.55

三、知息長短者，此對欲界定。若證欲界定時，宜是定明淨都不覺知息中相貌。今此中初得定時，即覺息中長短之相。云何為覺？若心定時，覺入息長，出息短。何以故？心既靜住於內，息隨心入故，入則知長。既心不緣外，故出則知短。

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.