Leviticus 15:2-4

2“Speak to the children of Israel, and say to them, ‘When any man has a bodily discharge, his discharge is unclean.

3This shall be [the law concerning] his uncleanness in his discharge: whether his body allows its discharge to flow or obstructs its flow; it is uncleanness in him.

4Every bed on which the one who has the discharge lies becomes unclean, and everything on which he sits becomes unclean.