Leviticus 15:23
And if it be on her bed, or on any thing whereon she sitteth, when he toucheth it, he shall be unclean until the even. And if it be on her bed, or on any thing whereon she sitteth, when he toucheth it, he shall be unclean until the even.
The verse belongs to the laws of physical uncleanness and cleansing given in Leviticus 12-15. Anyone who touched a bed or seat used by an unclean person had to wash, bathe, and remain unclean until evening. The required separation for the rest of the day kept the person from others while air and sunshine completed disinfection, helping prevent the spread of infectious disease. An affected object had to be made visibly clean first before the sanctuary's later cleansing with blood.
The regulation formed part of the sanctuary's yearly round of service, which typified Christ's once-for-all ministry in the heavenly sanctuary. As one of the object-lessons in Leviticus, the verse emphasizes the exceeding sinfulness of sin everywhere. Its detail about uncleanness becomes living and a blessing when read as pointing to Jesus Christ as the Lamb of God who takes away the sin of the world.
As part of Israel's cleansing laws, the verse serves as an example of the cleansing expected of God's people and is connected broadly to health reform and preparing the body as a clean dwelling for God's Spirit, without giving a specific explanation of its rule about touching a bed or seat.