佛說觀佛三昧海經 7.22

7.22

"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.