四分律比丘含注戒本 2.351

2.351

The Buddha was in Rājagṛha. At that time, the people were holding a festival. The two Śākyan sons, Nanda and Upananda, went together to watch theatrical performers, and also accepted food and drink, returning to the mountain toward evening. Kālodayin entered the city at night to beg for food, and a woman saw him in a flash of lightning and cried out: 'A ghost! A ghost!' The bhikṣus reported this fault to the Buddha, who rebuked them and formulated this precept.