SN54.20 — Discourse on the Destruction of the Taints

… It leads to the destruction of the taints. And how is mindfulness of breathing, when developed and cultivated, conducive to the abandonment of the fetters ...

to the uprooting of underlying tendencies ... to the full knowing of the course ... to the destruction of the taints?

Here a disciple goes to the forest or to the root of a tree ... and trains thus: I will breathe in contemplating relinquishment, I will breathe out contemplating relinquishment. Thus developed mindfulness of breathing, when cultivated, is conducive to the abandonment of the fetters ...