Leviticus 15:19

19.And if a woman have an issue. Women are now spoken of who suffer under a twofold issue of blood; for with almost all it occurs every month, (whence it is called menses, or menstruation,) and some labor under a constant hemorrhage. He declares both to be unclean; and, after menstruation, a certain period of separation is appointed, during which the law prohibited their cohabitation with men; but, if the blood flowed beyond the usual time, the time of purification is postponed until it ceased. Whence it appears, that in every shameful thing the Jews were reminded of their uncleanness, that thus they might be accustomed to modesty and seek after purity. And this still more clearly appears at the end of the chapter, where it is said, (v. 3l,) “Thus shall ye separate the children of Israel from their uncleanness; that they die not — when they defile my tabernacle.” God, I say, briefly sets forth His intention that He would drive away all profanation far from His people; because he desires sincerity to prevail amongst his worshippers, and cannot bear his tabernacle to be polluted by any stain.