四分律比丘含注戒本 1.574

1.574

The Buddha was in Śrāvastī. Viśākhā's mother invited the Buddha and the Saṃgha. When the maidservant announced that the time had arrived, she saw the bhikṣus bathing naked. Because of this, [Viśākhā] made eight vows, which were praised by the Buddha. The group of six [monks] constantly sought [bathing robes], and the bhikṣus reported the fault. The Buddha laid down the precept on this account.