[521] Sāvatthī . atha kho aññataro bhikkhu yena bhagavā .pe. ekamantaṃ nisinno kho so bhikkhu bhagavantaṃ etadavoca ko nu kho bhante hetu ko paccayo yena midhekacce jalābujā nāgā uposathaṃ upavasanti vossaṭṭhakāyā ca bhavantīti . (sabbaṃ vitthāretabbaṃ) . ayaṃ kho bhikkhu hetu ayaṃ paccayo yena midhekacce jalābujā nāgā uposathaṃ upavasanti vossaṭṭhakāyā ca bhavantīti.