[1384] On whatever occasion, Ānanda, a bhikkhu trains thus: 'Experiencing the mind (citta), I shall breathe out'; he trains thus: 'Experiencing the mind, I shall breathe in.' He trains thus: 'Gladdening the mind, I shall breathe out' … He trains thus: 'Concentrating the mind' … He trains thus: 'Liberating the mind, I shall breathe out'; he trains thus: 'Liberating the mind, I shall breathe in' — on that occasion, Ānanda, the bhikkhu dwells contemplating the mind in the mind, ardent, clearly comprehending, mindful, having removed covetousness and grief regarding the world. For what reason? I do not, Ānanda, speak of the development of concentration (samādhi) by mindfulness of breathing (ānāpānasati) for one of muddled mindfulness who lacks clear comprehension. Therefore, Ānanda, on that occasion the bhikkhu dwells contemplating the mind in the mind, ardent, clearly comprehending, mindful, having removed covetousness and grief regarding the world.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.