[294] "And how, bhikkhus, is mindfulness directed to the body (kāyagatā sati) developed, how is it cultivated, so that it is of great fruit and great benefit? Here, bhikkhus, a bhikkhu, gone to the forest, or gone to the root of a tree, or gone to an empty dwelling, sits down, having folded his legs crosswise, having set his body erect, having established mindfulness in front of him. Mindful, he breathes in; mindful, he breathes out. Breathing in long, he understands: 'I breathe in long'; or breathing out long, he understands: 'I breathe out long.' Breathing in short, he understands: 'I breathe in short'; or breathing out short, he understands: 'I breathe out short.' He trains thus: 'Experiencing the whole body, I shall breathe in'; he trains thus: 'Experiencing the whole body, I shall breathe out.' He trains thus: 'Calming the bodily formation, I shall breathe in'; he trains thus: 'Calming the bodily formation, I shall breathe out.' As he dwells thus diligent, ardent, and resolute, whatever memories and intentions based on the household life exist are abandoned. With their abandoning, the mind (citta) becomes steadied internally, settles down, becomes unified, and becomes concentrated. In this way too, bhikkhus, a bhikkhu develops mindfulness directed to the body.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.