四分律行事鈔資持記 2.471

2.471

The first precept. (The Buddha was in Śrāvastī; Udāyin's sexual desire was intense and his body became emaciated, so he thought of discharging [semen], and his sense faculties became joyful; the Buddha rebuked him and instituted the precept.) Indicating the title. Saying 'intentional' contrasts with the exception below for lack of deliberate intention.