[411] How does one train thus: "Calming the mental formation (cittasaṅkhāra), I shall breathe out"; how does one train thus: "Calming the mental formation, I shall breathe in"?
What is the mental formation? Perception and feeling (vedanā), by way of the long out-breath, are mental factors (cetasika); these dhammas, being bound up with the mind (citta), are mental formations. Calming, causing to cease, and stilling those mental formations, one trains. Perception and feeling, by way of the long in-breath, are mental factors; these dhammas, being bound up with the mind, are mental formations. Calming, causing to cease, and stilling those mental formations, one trains. Perception and feeling, by way of experiencing the mental formation on the out-breath, by way of experiencing the mental formation on the in-breath, are mental factors; these dhammas, being bound up with the mind, are mental formations. Calming, causing to cease, and stilling those mental formations, one trains. By way of the out-breaths and in-breaths while calming the mental formation, feeling is the establishment (upaṭṭhāna); mindfulness is the knowledge (ñāṇa) of contemplation. Feeling is the establishment, not mindfulness; mindfulness is both the establishment and the mindfulness itself. With that mindfulness and with that knowledge (ñāṇa) one contemplates that feeling. Hence it is said: "The development of the establishment of mindfulness (satipaṭṭhāna) consisting in contemplation of feelings in feelings."
"Contemplates": how does one contemplate that feeling? … Thus one contemplates that feeling.
"Development": there are four kinds of development … development in the sense of repeated practice. The out-breaths and in-breaths while calming the mental formation are purity of virtue (sīlavisuddhi) in the sense of restraint … For one who understands the mind's one-pointedness and non-distraction by way of the out-breaths and in-breaths while calming the mental formation … understanding this, one brings the faculties into unity; hence it is said: "and one penetrates the meaning of peace." There are eight knowledges of contemplation, eight recollections of establishment (upaṭṭhānānussati), and four Suttanta grounds in the contemplation of feelings in feelings.
End of the recitation section (bhāṇavāra).
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.