佛說觀佛三昧海經 7.22

7.22

「爾時國王請佛入城，龍王怒曰：『汝奪我利，吾滅汝國。』佛告大王：『檀越先歸，佛自知時。』爾時國王為佛作禮逡巡而退。爾時龍王及羅剎女，五體投地求佛授戒，佛即如法為說三歸五戒之法，龍王聞已心大歡喜，龍王眷屬百千諸龍，從池而出為佛作禮，如來應時隨龍音類為其說法，聞法歡喜，佛勅目連為其受戒。

"At that time the king invited the Buddha to enter the city. The nāga king said angrily: 'If you take away my benefit, I will destroy your kingdom.' The Buddha said to the great king: 'Let the dānapati return first; the Buddha himself knows the proper time.' Then the king paid homage to the Buddha and hesitatingly withdrew. At that time the nāga king and the rākṣasīs threw their five limbs to the ground, begging the Buddha to bestow the precepts. The Buddha then expounded the Dharma of the three refuges and the five precepts for them in accordance with the Dharma. When the nāga king heard this, his heart was filled with great joy. The nāga king's retinue of hundreds of thousands of nāgas came out from the pool and paid homage to the Buddha. The Tathāgata immediately expounded the Dharma for them in the voice and dialect of nāgas. Hearing the Dharma, they were delighted, and the Buddha instructed Maudgalyāyana to bestow the precepts upon them.