四分律比丘含注戒本 2.205

2.205

佛在舍衛。尼聞教授師來，出迎供給，六群生嫉，云：「彼無實，但為食故教授尼也。」比丘以過白佛，因而制戒。

The Buddha was in Śrāvastī. When the bhikṣuṇīs heard that the instructing master was coming, they went out to welcome and serve him. The group of six became jealous and said: “He has no sincerity; he instructs the bhikṣuṇīs merely for food.” The bhikṣus reported this fault to the Buddha, who instituted the rule on account of it.