Herein, monastics, what are the sixteen modes of mindfulness while breathing?

Here, monastics, [a monastic] while breathing in mindfully, knows as it really is: I am breathing in mindfully, while breathing out mindfully, knows as it really is: I am breathing out mindfully.

1. While breathing in long, he knows as it really is: I am breathing in long, while breathing out long, he knows as it really is: I am breathing out long.

2. While breathing in short, he knows as it really is: I am breathing in short, while breathing out short, he knows as it really is: I am breathing out short.

3. While breathing in and experiencing the whole bodily conditions he knows as it really is: I am breathing in and experiencing the whole bodily conditions, while breathing out and experiencing the whole bodily conditions he knows as it really is: I am breathing out and experiencing the whole bodily conditions.

4. While breathing in and experiencing joy he knows as it really is: I am breathing in and experiencing joy, while breathing out and experiencing joy he knows as it really is: I am breathing out and experiencing joy.

5. While breathing in and experiencing pleasure he knows as it really is: I am breathing in and experiencing pleasure, while breathing out and experiencing pleasure he knows as it really is: I am breathing out and experiencing pleasure.

6. While breathing in and making the bodily conditions calm he knows as it really is: I am breathing in and making the bodily conditions calm, while breathing out and making the bodily conditions calm he knows as it really is: I am breathing out and making the bodily conditions calm.

7. While breathing in and experiencing the mental conditions he knows as it really is: I am breathing in and experiencing the mental conditions, while breathing out and experiencing the mental conditions he knows as it really is: I am breathing out and experiencing the mental conditions.

8. While breathing in and making the mental conditions calm he knows as it really is: I am breathing in and making the mental conditions calm, while breathing out and making the making the mental conditions calm he knows as it really is: I am breathing out and making the mental conditions calm.

9. While breathing in and experiencing the mind he knows as it really is: I am breathing in and experiencing the mind, while breathing out and experiencing the mind he knows as it really is: I am breathing out and experiencing the mind.

10. While breathing in (thinking), my mind is gladdened he knows as it really is: I am breathing in (thinking), my mind is gladdened, while breathing out (thinking), my mind is gladdened he knows as it really is: I am breathing out (thinking), my mind is gladdened.

11. While breathing in and concentrating the mind he knows as it really is: I am breathing in and concentrating the mind, while breathing out and concentrating the mind he knows as it really is: I am breathing out and concentrating the mind.

12. While breathing in (thinking), my mind is free he knows as it really is: I am breathing in (thinking), my mind is free, while breathing out (thinking), my mind is free he knows as it really is: I am breathing out (thinking), my mind is free.

13. And so for contemplating impermanence…

14. Contemplating dispassion…

15. Contemplating cessation…

16. While breathing in and contemplating letting go he knows as it really is: I am breathing in and contemplating letting go, while breathing out and contemplating letting go he knows as it really is: I am breathing out and contemplating letting go.

This, monastics, is the sixteen modes of mindfulness while breathing.