佛說觀佛三昧海經 7.23

7.23

"Then Maudgalyāyana entered the samādhi of doing as one wills, and immediately transformed his body into hundreds of thousands of myriads of garuḍa kings, each king treading upon five nāgas with his feet and dwelling in the sky. At that time the young nāgas spoke these words: 'The Buddha instructed the upādhyāya to bestow the precepts upon us; why does the upādhyāya assume a terrifying form?' Maudgalyāyana told them: 'For many kalpas, where there was nothing to fear, you arbitrarily gave rise to thoughts of fear; where there was no anger, you gave rise to thoughts of anger; and where there was no harm, you arbitrarily gave rise to thoughts of harm. I am truly a human, but because of your wicked minds, you see me as a bird.' At that time the nāga king, out of fear, vowed of his own accord not to kill or vex living beings, thereby generating a wholesome mind. Maudgalyāyana immediately returned to his original form and expounded the five precepts for them.