Leviticus 15:18-20

New International Version

¹⁸ When a man has sexual relations with a woman and there is an emission of semen,^(A) 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^(B) 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.