Leviticus 15:1-3

And Jehovah spake unto Moses and to Aaron, saying, Speak unto the children of Israel, and say unto them, When any man hath an issue out of his flesh, because of his issue he is unclean. And this shall be his uncleanness in his issue: whether his flesh run with his issue, or his flesh be stopped from his issue, it is his uncleanness.