坐禪三昧經 1.68

1.68

捨風門住離麁觀法，離麁觀法知息無常，此名轉觀。觀五陰無常，亦念入息出息生滅無常。見初頭息無所從來，次觀後息亦無跡處，因緣合故有，因緣散故無，是名轉觀法。

"Relinquishing fixing on the aperture of the breath and leaving the method of coarse contemplation, through leaving the method of coarse contemplation one knows that the breath is anitya; this is called 'shifting contemplation.' One contemplates the five aggregates as anitya, and also contemplates the inhalation and exhalation as arising, ceasing, and anitya. One sees that the initial breath comes from nowhere, and next contemplates that the subsequent breath leaves no trace; because causes and conditions combine, it exists; because causes and conditions disperse, it does not exist. This is called the 'method of shifting contemplation.'"