UD 3.5  Mahāmoggallāna sutta - Mahāmoggallāna

Evaṁ me sutaṁ— ekaṁ samayaṁ bhagavā sāvatthiyaṁ viharati jetavane anāthapiṇḍikassa ārāme. Tena kho pana samayena āyasmā mahāmoggallāno bhagavato avidūre nisinno hoti pallaṅkaṁ ābhujitvā ujuṁ kāyaṁ paṇidhāya kāyagatāya satiyā ajjhattaṁ sūpaṭṭhitāya.

Thus have I heard—At one time, the Blessed One was dwelling at Sāvatthi, in Jeta’s grove, Anāthapiṇḍika’s park. Now, at that time, the venerable Mahāmoggallāna was sitting not far from the Blessed One, having folded his legs in a |cross-legged sitting position::meditation posture [pallaṅka]|, aligning his body upright, and with |mindfulness immersed in the body::mindfulness related to the body, focused within [kāyagata + sati]|, |well-established::fully engaged [sūpaṭṭhita]| internally.

Addasā kho bhagavā āyasmantaṁ mahāmoggallānaṁ avidūre nisinnaṁ pallaṅkaṁ ābhujitvā ujuṁ kāyaṁ paṇidhāya kāyagatāya satiyā ajjhattaṁ sūpaṭṭhitāya.

The Blessed One saw the venerable Mahāmoggallāna sitting not far away, having folded his legs in a cross-legged sitting position, aligning his body upright, and with mindfulness immersed in the body, well-established internally.

Atha kho bhagavā etamatthaṁ viditvā tāyaṁ velāyaṁ imaṁ udānaṁ udānesi:

Then, understanding the significance of this, the Blessed One at that time expressed this inspired utterance:

“Sati kāyagatā upaṭṭhitā,
Chasu phassāyatanesu saṁvuto;
Satataṁ bhikkhu samāhito,
Jaññā nibbānamattano”ti.

“Established in the mindfulness immersed in the body,
restrained in the six |sense bases::fields of sense impressions [phassāyatana]|;
A bhikkhu who is continuously |collected::composed, settled [samāhita]|,
can realize |Nibbāna::complete cooling, letting go of everything, deathless, freedom from calamity, the non-disintegrating [nibbāna]| for himself.”