[931] **A bhikkhu, mindful, conducting himself within the boundaries.** "Bhikkhu": a bhikkhu who is a good worldling (kalyāṇaputhujjana), or a bhikkhu who is a trainee (sekkha). "Mindful": he is possessed of mindfulness for four reasons: developing the establishment of mindfulness (satipaṭṭhāna) of contemplating the body in the body, he is mindful; developing the establishment of mindfulness of contemplating … in feelings (vedanā), … in the mind (citta), … of contemplating dhammas in dhammas, he is mindful — he is called "mindful." "Conducting himself within the boundaries": there are four boundaries (pariyanta): the boundary of restraint by virtue (sīlasaṃvara), the boundary of restraint of the sense faculties (indriyasaṃvara), the boundary of moderation in eating (bhojane mattaññutā), and the boundary of devotion to wakefulness (jāgariyānuyoga).
What is the boundary of restraint by virtue? Here a bhikkhu is virtuous; he dwells restrained by the restraint of the Pātimokkha, accomplished in conduct and resort, seeing danger in the slightest faults; having undertaken them, he trains in the training rules. Reflecting on the putrid state within, he conducts himself inside the boundary of restraint by virtue; he does not break through the boundary line. This is the boundary of restraint by virtue.
What is the boundary of restraint of the sense faculties? Here a bhikkhu, having seen a form with the eye, does not grasp at its signs or its features. Since, if he were to dwell with the eye faculty unrestrained, evil, unwholesome states of covetousness and grief might flow in upon him, he practices for its restraint; he guards the eye faculty, he undertakes the restraint of the eye faculty. Having heard a sound with the ear, having smelt an odor with the nose, having tasted a flavor with the tongue, having touched a tangible object with the body, having cognized a mental phenomenon with the mind, he does not grasp at its signs or its features. Since, if he were to dwell with the mind faculty unrestrained, evil, unwholesome states of covetousness and grief might flow in upon him, he practices for its restraint; he guards the mind faculty, he undertakes the restraint of the mind faculty. Reflecting on the exposition on burning (ādittapariyāya), he conducts himself inside the boundary of restraint of the sense faculties; he does not break through the boundary line. This is the boundary of restraint of the sense faculties.
What is the boundary of moderation in eating? Here a bhikkhu, reflecting wisely, takes his food: not for amusement, not for intoxication, not for adornment, not for beautification, but only for the maintenance and sustenance of this body, for the allaying of affliction, for assisting the holy life, considering: "Thus I shall terminate the old feeling and shall not arouse a new feeling; and I shall be healthy and blameless and shall dwell in comfort." Reflecting on the similes of the greasing of an axle, the dressing of a wound, and the flesh of a son, he conducts himself inside the boundary of moderation in eating; he does not break through the boundary line. This is the boundary of moderation in eating.
What is the boundary of devotion to wakefulness? Here a bhikkhu, during the day, purifies his mind of obstructive states by walking back and forth and by sitting; in the first watch of the night he purifies his mind of obstructive states by walking back and forth and by sitting; in the middle watch of the night he lies down on his right side in the lion's posture, placing one foot upon the other, mindful and clearly comprehending, having attended to the perception of rising; in the last watch of the night, having risen, he purifies his mind of obstructive states by walking back and forth and by sitting. Reflecting on the dwelling of one who has a single auspicious night (bhaddekaratta), he conducts himself inside the boundary of devotion to wakefulness; he does not break through the boundary line. This is the boundary of devotion to wakefulness. Thus: **a bhikkhu, mindful, conducting himself within the boundaries.**
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.