Numbers 19:21
“And it shall be a perpetual statute unto them, that he that sprinkleth the water of separation shall wash his clothes; and he that toucheth the water of separation shall be unclean until even.”
And the clean person shall sprinkle upon the unclean on the third day, and on the seventh day: and on the seventh day he shall purify himself, and wash his clothes, and bathe himself in water, and shall be clean at even.
But the man that shall be unclean, and shall not purify himself, that soul shall be cut off from among the congregation, because he hath defiled the sanctuary of the Lord: the water of separation hath not been sprinkled upon him; he is unclean.
And it shall be a perpetual statute unto them, that he that sprinkleth the water of separation shall wash his clothes; and he that toucheth the water of separation shall be unclean until even.
And whatsoever the unclean person toucheth shall be unclean; and the soul that toucheth it shall be unclean until even.
Counter-Arguments
The strongest case that this verse does not belong in this theme.

Related Verses
“And he that gathereth the ashes of the heifer shall wash his clothes, and be unclean until the even: and it shall be unto the children of Israel, and unto the stranger that sojourneth among them, for a statute for ever.”
“And whosoever toucheth her bed shall wash his clothes, and bathe himself in water, and be unclean until the even.”
“And he that burneth her shall wash his clothes in water, and bathe his flesh in water, and shall be unclean until the even.”
“So they shall wash their hands and their feet, that they die not: and it shall be a statute for ever to them, even to him and to his seed throughout their generations.”
“And whatsoever the unclean person toucheth shall be unclean; and the soul that toucheth it shall be unclean until even.”