四分律比丘含注戒本 2.513

2.513

The Buddha was in the country of Pārileyyaka. Nāgapāla was attending upon the Buddha. It is the regular practice of all Buddhas that when walking back and forth, an attendant stands at the head of the walkway. During the first, middle, and last watches of the night, he called upon the Buddha to return, and then wore his cloak inside-out and made frightful shapes to scare the Buddha. The following morning the saṃgha was assembled, and on this account he laid down this precept.