Leviticus 15:31-33

31“ ‘You must keep the Israelites separate from things that make them unclean, so they will not die in their uncleanness for defiling my dwelling place, which is among them.’ ” 32These are the regulations for a man with a discharge, for anyone made unclean by an emission of semen, 33for a woman in her monthly period, for a man or a woman with a discharge, and for a man who has sexual relations with a woman who is ceremonially unclean.