Leviticus 15:19
And if a woman have an issue, and her issue in her flesh be blood, she shall be put apart seven days: and whosoever toucheth her shall be unclean until the even. And if a woman have an issue, and her issue in her flesh be blood, she shall be put apart seven days: and whosoever toucheth her shall be unclean until the even.
Leviticus 15:19 belongs to the laws in chapters 12-15 regulating uncleanness, which give laws about individual purity. It is part of the law of cleansing in which bodily uncleanness had to be removed so that a person or object was visibly clean before the sanctuary's deeper cleansing by blood. It is part of God's system of sanitation for preventing infectious disease by cleanliness, keeping matter in its rightful place so that filth diseases and harmful germ life in the wrong place are avoided, using rigid but simple restrictions, air, sunshine, running water, and isolation to prevent communication of infection to others.
Whoever touched the patient, or bed, or any vessel used, must wash clothes and bathe in water and be unclean until the even, which means isolating from others for the remainder of that day to allow air and sunshine to complete disinfection, while the recovered patient must number seven days for cleansing and wash clothes and bathe flesh in running water, and this isolation prevented epidemics by not permitting careless infection of others. Neglecting or forgetting these cleansing instructions made one a criminal to be stoned to death, and carrying them out gave Israel a camp of very low mortality, with disease recorded only when the people broke the rules and indulged in things that caused disease. Grouped with the regulations concerning leprosy, the laws to which the verse belongs present a fitting type of sin.
The verse shows the exceeding sinfulness of sin and stands as one of God's mighty object-lessons in Leviticus. It must be read remembering that all the sacrifices and slain beasts of Leviticus point forward to Jesus Christ, the Lamb of God who takes away the sin of the world, and seeing Him in these details of laws and regulations gives them new life and makes them a blessing instead of dry and wearisome reading. It is among the cleansing truths given to ancient Israel that believers should not abandon, as an example of the bodily purity associated with preparing a clean vessel for God's Spirit. The individual purity laws of the chapter have a parallel in similar practices and laws among the Zulus.