六妙法門 1.36

1.36

復次，行者當數息時，非但成就觀智，識前法虛假，亦復善巧覺了觀照之心無有自性，虛誑不實，離知覺想，是則於數息中成就還門。

Furthermore, when the practitioner counts the breath, not only does one achieve the wisdom of contemplation and recognize that the preceding dharmas are unreal and provisional, but one also skillfully perceives and understands that the contemplating and illuminating mind is devoid of inherent nature, deceptive, unreal, and free from notions of perception and sensation—this is achieving the gate of turning back within counting the breath.