And if any man's semen go out from him, then he shall wash all his flesh in water, and be unclean until the evening.
Read Chapter 15
George Leo Haydock
Evening, whether the action were lawful or not. (Menochius)
Some explain this verse, of nocturnal inconveniences; and ver. 18, of the act of marriage. The latter rendered unclean only in as much as it hindered a person from partaking of any thing sacred, though he might perform the duties of life. (Calmet)
This law was to lay some restraint on the too frequent use of marriage. (Theodoret) (Du Hamel)