SN 29.3

Uposathasutta

Ekaṁ samayaṁ bhagavā sāvatthiyaṁ viharati jetavane anāthapiṇḍikassa ārāme. Atha kho aññataro bhikkhu yena bhagavā tenupasaṅkami; upasaṅkamitvā ekamantaṁ nisīdi. Ekamantaṁ nisinno kho so bhikkhu bhagavantaṁ etadavoca: “ko nu kho, bhante, hetu, ko paccayo, yena m’idhekacce aṇḍajā nāgā uposathaṁ upavasanti vossaṭṭhakāyā ca bhavantī”ti?

Sabbath

At one time the Buddha was staying near Sāvatthī in Jeta’s Grove, Anāthapiṇḍika’s monastery. Then a mendicant went up to the Buddha, sat down to one side, and said to him: “Sir, what is the cause, what is the reason why some egg-born dragons keep the sabbath, having transformed their bodies?”

“Idha, bhikkhu, ekaccānaṁ aṇḍajānaṁ nāgānaṁ evaṁ hoti: ‘mayaṁ kho pubbe kāyena dvayakārino ahumha, vācāya dvayakārino, manasā dvayakārino. Te mayaṁ kāyena dvayakārino, vācāya dvayakārino, manasā dvayakārino, kāyassa bhedā paraṁ maraṇā aṇḍajānaṁ nāgānaṁ sahabyataṁ upapannā. Sacajja mayaṁ kāyena sucaritaṁ careyyāma, vācāya sucaritaṁ careyyāma, manasā sucaritaṁ careyyāma, evaṁ mayaṁ kāyassa bhedā paraṁ maraṇā sugatiṁ saggaṁ lokaṁ upapajjeyyāma. Handa mayaṁ etarahi kāyena sucaritaṁ carāma, vācāya sucaritaṁ carāma, manasā sucaritaṁ carāmā’ti. Ayaṁ kho, bhikkhu, hetu, ayaṁ paccayo, yena m’idhekacce aṇḍajā nāgā uposathaṁ upavasanti vossaṭṭhakāyā ca bhavantī”ti.

“Mendicant, it’s when some egg-born dragons think: ‘In the past we did both kinds of deeds by body, speech, and mind. When the body broke up, after death, we were reborn in the company of the egg-born dragons. If today we do good things by body, speech, and mind, when the body breaks up, after death, we may be reborn in a good place, a heavenly realm. Come, let us do good things by way of body, speech, and mind.’ This is the cause, this is the reason why some egg-born dragons keep the sabbath, having transformed their bodies.”