四分律比丘含注戒本 3.383

3.383

佛在拘羅國。六群安佛在下房，己在上房住。行頭陀比丘舉過白佛，因訶制戒。

The Buddha was in the country of Kuru. The group of six installed the Buddha in a lower room while dwelling in an upper room themselves. Bhikṣus practicing dhūta raised the fault and reported it to the Buddha, who thereupon rebuked them and instituted the precept.