Cattāri Brahmavihārā

37. Develop the meditation that is mindfulness of in-and-out breathing. Mindfulness of in-and-out breathing is of great fruit, of great advantage.

And how is mindfulness of in-and-out breathing developed, how is it made much of, how is it of great fruit, great advantage? Concerning this, one who has gone to the forest, to the root of a tree or to an empty place, sits down cross-legged with the back straight, establishing mindfulness in front of him.

Mindfully one breathes in, mindfully one breathes out. Breathing in a long breath one knows: ‘I am breathing in a long breath;” breathing out a long breath one knows: “I am breathing out a long breath.” Breathing in a short breath one knows: “I am breathing in a short breath;” breathing out a short breath one knows: “I am breathing out a short breath.”

One trains oneself, thinking: “Breathing in I shall experience the whole body.” One trains oneself, thinking: “Breathing out I shall experience the whole body.” One trains oneself, thinking: “Breathing in I will tranquillize bodily activities.” One trains oneself, thinking: “Breathing out I will tranquillize bodily activities.”

Majjhima Nikaya I.425