佛祖統紀 3.90

3.90

In the winter of the eighth year (dīnghài), the Buddha was in the country of Vaiśālī. Because Sudinna, a son of a merchant, upheld faith and left household life, but later returned to his native village to engage in impure conduct with his former mate ('former' means his former wife; 'mate' means pair/consort), the bhikṣus brought up the offense and reported it to the Buddha. The Buddha immediately gathered the assembly and rebuked him, saying: 'What you have done lacks deportment and pure conduct; it is what should not be done.' He began to institute the precept against unchastity, allowing that the first offender had not yet incurred guilt under a established rule (Mahāsaṅghika-vinaya).