Leviticus 15:23

And if it be on her bed, or on anything whereon she sitteth ,.... That is, if any person or thing should be upon her bed or seat; a vessel on her bed, or a vessel upon a vessel, as Aben Ezra expresses it:

when he toucheth it ; that person or thing that should be on her bed or seat, as well as touch her bed or seat:

shall be unclean until the even ; in a ceremonial sense; so defiling was a woman in such circumstances, and to whom the Scriptures often compare unclean persons and things: and Pliny F9 Nat. Hist. l. 7. c. 15. speaks of menstrues as very infectious, or worse, to various creatures and things, in a natural way.