SN54.11 — The Discourse at Icchānaṅgala
At one time, the Blessed One was staying at Icchānaṅgala in the Icchānaṅgala forest grove.
There, the Blessed One addressed the disciples: Disciples, I wish to remain in seclusion for three months. I should not be approached by anyone except for one who brings me alms food.
Yes, venerable sir, those disciples replied to the Blessed One. Then no one approached the Blessed One except for one who brought him alms food.
Then, at the end of those three months, the Blessed One emerged from seclusion and addressed the disciples: Disciples, if wanderers of other sects should ask you, In what dwelling did the ascetic Gotama mostly dwell during the rains residence? being asked thus, you should reply to those wanderers of other sects: The Blessed One mostly dwelt in the concentration by mindfulness of breathing.
Here I breathe in mindfully, I breathe out mindfully.
Breathing in long, I know: I breathe in long; or breathing out long, I know: I breathe out long.
Breathing in short, I know: I breathe in short; or breathing out short, I know: I breathe out short.
Knowing: I will breathe in experiencing the whole body; Knowing:: I will breathe out experiencing the whole body.
Knowing: I will breathe in calming the bodily formation; Knowing: I will breathe out calming the bodily formation.
If one speaking rightly would speak, they might say of me: The noble dwelling, the divine dwelling, the Tathāgatas dwelling.
Speaking rightly, one would speak of the concentration by mindfulness of breathing as the noble dwelling, the divine dwelling, the Tathāgatas dwelling.
Disciples, for those disciples who are trainees, who have not attained their minds ideal, who dwell aspiring for the unsurpassed security from bondage, the concentration by mindfulness of breathing, when developed and cultivated, leads to the destruction of the taints.
For those disciples who are arahants, taint-free, who have lived the holy life, done what had to be done, laid down the burden, reached their own goal, destroyed the fetters of being, and are completely liberated through final knowing, the concentration by mindfulness of breathing, when developed and cultivated, leads to a pleasant dwelling in this very life and to mindfulness and clear knowing.
If one speaking rightly would speak, they might say of me: The noble dwelling, the divine dwelling, the Tathāgatas dwelling.
Speaking rightly, one would speak of the concentration by mindfulness of breathing as the noble dwelling, the divine dwelling, the Tathāgatas dwelling.
It is called ariyavihāra, brahmavihāra, and tathāgatavihāra.