四分律比丘含注戒本 3.299

3.299

佛在舍衛。六群與不恭敬反抄衣人說法。時比丘聞之，少欲知慚者舉過。佛因訶制戒。

The Buddha was in Śrāvastī. The group of six expounded the Dharma to a disrespectful person whose robe was pulled up over their shoulders. At that time bhikṣus heard of it, and those of few desires and a sense of shame reported the fault. The Buddha thereupon rebuked them and formulated the precept.