佛說觀佛三昧海經 7.23

7.23

「爾時目連入如意定，即自化身作百千億金翅鳥王，一一鳥王足躡五龍住在虛空。時諸小龍而作是言：『佛勅和上為我受戒，和上云何作恐怖像？』目連告曰：『汝於多劫不恐怖中橫生怖想、於無瞋恚生瞋恚想、於無害所橫生害想，我實是人，汝惡心故見我是鳥。』爾時龍王以恐怖故，自誓不殺不惱眾生以發善心，目連即時還復本身為說五戒。

"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.