六妙法門 1.37

1.37

復次，行者當數息時，非但不得所觀、能觀，以惠方便亦不得無能觀、所觀，以本淨法性，如虛空不可分別故。爾時行者心同法性，寂然不動，是則於數息中成就淨門。

Furthermore, when the practitioner counts the breath, not only does one not apprehend the contemplated or the contemplator, but by expedient means of wisdom one also does not apprehend the absence of the contemplator and the contemplated, because the fundamentally pure dharma nature is like space, beyond discrimination. At that time, the practitioner's mind is identical to the dharma nature, tranquil and unmoving—this is achieving the gate of purification within counting the breath.