四分律比丘含注戒本 1.93

1.93

The Buddha was in Vaiśālī, expounding the contemplation of impurity for the bhikṣus. Having practiced this concentration, they grew disgusted with their bodies and lives, praising death and encouraging death. The bhikṣu Nandi was hired to kill people, terrifying the householders. The Buddha, learning of this matter, then taught the methods of dhyāna. The bhikṣus cultivated them and all realized the higher fruits. Because of rebuking the aforementioned fault, he instituted this precept.