ritual purification

Ritual purification is a feature of many religions. The aim of these rituals is to remove specifically defined uncleanliness prior to a particular type of activity, and especially prior to the worship of a deity. This ritual uncleanliness is not however identical with ordinary physical impurity, such as dirt stains; nevertheless, all body fluids are generally considered ritually unclean, and some religions have special treatment of semen and menses, which are viewed as particularly unclean.
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