18. After a man and a woman have sexual intercourse, they must each bathe in water, and they will remain unclean until the next evening.
19. “Whenever a woman has her menstrual period, she will be ceremonially unclean for seven days. Anyone who touches her during that time will be unclean until evening.
20. Anything on which the woman lies or sits during the time of her period will be unclean.