At Savatthi. There the Blessed One said, "Monks, do you develop mindfulness of in-&-out breathing?"
When this was said, Ven. Arittha replied to the Blessed One, "I develop mindfulness of in-&-out breathing, lord."
"But how do you develop mindfulness of in-&-out breathing, Arittha?"
"Having abandoned sensual desire for past sensual pleasures, lord, having done away with sensual desire for future sensual pleasures, and having thoroughly subdued perceptions of irritation with regard to internal & external events, I breathe in mindfully and breathe out mindfully."[1]
"There is that mindfulness of in-&-out breathing, Arittha. I don't say that there isn't. But as to how mindfulness of in-&-out breathing is brought in detail to its culmination, listen and pay close attention. I will speak."
"As you say, lord," Ven. Arittha responded to the Blessed One.
The Blessed One said, "And how, Arittha, is mindfulness of in-&-out breathing brought in detail to its culmination? There is the case where a monk, having gone to the wilderness, to the shade of a tree, or to an empty building, sits down folding his legs crosswise, holding his body erect, and setting mindfulness to the fore.[2] Always mindful, he breathes in; mindful he breathes out.
"[1] Breathing in long, he discerns, 'I am breathing in long'; or breathing out long, he discerns, 'I am breathing out long.' [2] Or breathing in short, he discerns, 'I am breathing in short'; or breathing out short, he discerns, 'I am breathing out short.' [3] He trains himself, 'I will breathe in sensitive to the entire body.'[3] He trains himself, 'I will breathe out sensitive to the entire body.' [4] He trains himself, 'I will breathe in calming bodily fabrication.'[4] He trains himself, 'I will breathe out calming bodily fabrication.'
"[5] He trains himself, 'I will breathe in sensitive to rapture.' He trains himself, 'I will breathe out sensitive to rapture.' [6] He trains himself, 'I will breathe in sensitive to pleasure.' He trains himself, 'I will breathe out sensitive to pleasure.' [7] He trains himself, 'I will breathe in sensitive to mental fabrication.'[5] He trains himself, 'I will breathe out sensitive to mental fabrication.' [8] He trains himself, 'I will breathe in calming mental fabrication.' He trains himself, 'I will breathe out calming mental fabrication.'
"[9] He trains himself, 'I will breathe in sensitive to the mind.' He trains himself, 'I will breathe out sensitive to the mind.' [10] He trains himself, 'I will breathe in satisfying the mind.' He trains himself, 'I will breathe out satisfying the mind.' [11] He trains himself, 'I will breathe in steadying the mind.' He trains himself, 'I will breathe out steadying the mind.' [12] He trains himself, 'I will breathe in releasing the mind.' He trains himself, 'I will breathe out releasing the mind.'[6]
"[13] He trains himself, 'I will breathe in focusing on inconstancy.' He trains himself, 'I will breathe out focusing on inconstancy.' [14] He trains himself, 'I will breathe in focusing on dispassion.'[7] He trains himself, 'I will breathe out focusing on dispassion.' [15] He trains himself, 'I will breathe in focusing on cessation.' He trains himself, 'I will breathe out focusing on cessation.' [16] He trains himself, 'I will breathe in focusing on relinquishment.' He trains himself, 'I will breathe out focusing on relinquishment.'
"This, Arittha, is how mindfulness of in-&-out breathing is brought in detail to its culmination."