Leviticus 15:17-23

17Any clothing or leather that has semen on it must be washed with water, and it will be unclean till evening. 18When 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. 21Anyone who touches her bed will be unclean; they must wash their clothes and bathe with water, and they will be unclean till evening. 22Anyone who touches anything she sits on will be unclean; they must wash their clothes and bathe with water, and they will be unclean till evening. 23Whether it is the bed or anything she was sitting on, when anyone touches it, they will be unclean till evening.