四分律比丘含注戒本 3.183

3.183

The Buddha was in Śrāvastī. A householder prepared an offering of food, personally serving it. When the group of six received the food, they scooped out the center of the bowl so that it appeared empty. The householder criticized them, saying: "Insatiable in receiving food, like oxen, donkeys, horses, camels, pigs, and dogs." The bhikṣus reported it to the Buddha, who consequently rebuked them and formulated the precept.