四分律比丘含注戒本 2.708

2.708

The Buddha was in Śrāvastī. The group-of-six listened to other bhikṣus quarreling and then reported it to the other party, causing the disputes in the Saṃgha to be impossible to quell. The bhikṣus reported their fault, and the Buddha thereupon rebuked them and instituted the rule.