Leviticus 20:18

People, if the action become public; otherwise the man may be purified, chap xv. 24. This intemperance was by a positive law declared a mortal offence in the Jews, though in itself it might be venial. (Sanchez ix. 21.) The text shews that the woman here gives her consent. --- And she open. Hence she deserves to die, for exposing herself and her children to great danger. (Haydock)