[409] How does one train thus: "Experiencing happiness (sukha), I shall breathe in"?
Happiness: there are two kinds of happiness — bodily happiness and mental happiness.
What is bodily happiness? Whatever bodily comfort there is, whatever bodily happiness is felt, the comfortable, pleasant feeling (vedanā) born of body-contact — this is bodily happiness.
What is mental happiness? Whatever mental happiness there is, the comfort and happiness felt born of mind-contact, the comfortable, pleasant feeling born of mind-contact — this is mental happiness.
How are those happinesses known? For one who understands the one-pointedness and non-distraction of the mind (citta) by way of the long out-breath, mindfulness (sati) is established; by that mindfulness and that knowledge (ñāṇa), those happinesses are known. For one who understands the one-pointedness and non-distraction of the mind by way of the long in-breath, mindfulness is established; by that mindfulness and that knowledge, those happinesses are known. … For one realizing what is to be realized, those happinesses are known. Thus are those happinesses known.
By way of the out-breaths and in-breaths of one experiencing happiness, feeling is the establishment (upaṭṭhāna); mindfulness is the knowledge of contemplation (anupassanā-ñāṇa). Feeling is the establishment, not mindfulness; mindfulness is both the establishment and mindfulness itself. By that mindfulness and that knowledge he contemplates that feeling. Hence it is said: "the development (bhāvanā) of the establishment of mindfulness (satipaṭṭhāna) consisting in contemplating feelings in feelings."
He contemplates: how does he contemplate that feeling? He contemplates it as impermanent … Thus he contemplates that feeling.
Development: there are four kinds of development … development in the sense of repeated practice. The out-breaths and in-breaths of one experiencing happiness are purification of virtue in the sense of restraint … For one who understands the one-pointedness and non-distraction of the mind by way of the out-breaths and in-breaths of one experiencing happiness … understanding, he brings the faculties together in unity; hence it is said: "and he penetrates the meaning of calm."
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.