Question: where does it say in the bible about periods?
Answer: In the third book of the Pentateuch or Torah and particularly in the Code of legal purity (or Provisions for clean and unclean) of the Mosaic Law (Leviticus 11:1-15:33), it is stated that a woman undergoing menstruation is perceived as unclean for seven days and whoever touches her shall be unclean until evening (see ...