18. When a man has sexual relations with a woman and there is an emission of semen, both of them must bathe with water, and they will be unclean till evening.
19. “ ‘When a woman has her regular flow of blood, the impurity of her monthly period will last seven days, and anyone who touches her will be unclean till evening.
20. “ ‘Anything she lies on during her period will be unclean, and anything she sits on will be unclean.