Numbers 19:19-20

19and the clean shall sprinkle it on the unclean on the third day, and on the seventh day; and he shall purify him on the seventh day; and he shall wash his garments, and bathe himself in water, and shall be clean at even.

20And the man that is unclean, and doth not purify himself, that soul shall be cut off from the midst of the congregation, for he hath defiled the sanctuary of Jehovah: the water of separation hath not been sprinkled on him: he is unclean.