四分律比丘含注戒本 3.289

3.289

佛在舍衛。六群水中大小便、涕唾。居士譏言：「如猪、狗、牛、驢、駱駝。」比丘舉過，佛因制戒。

The Buddha was in Śrāvastī. The group of six voided feces, urine, mucus, and saliva into water. Laypeople criticized them, saying: "They are like pigs, dogs, cattle, donkeys, and camels." Bhikṣus reported the fault, and the Buddha thereupon formulated the precept.