Numbers 19:17-21

17“For the unclean one, they are to take some of the ash of the burnt purification offering, and pour some fresh water into a jar.

18Then a clean person will take some hyssop, dip it into the water, and, sprinkle it on the tent, all of the furnishings, and the people who were there, as well as the one touching the bone, the one killed, the corpse or the grave.

19The clean person will sprinkle the unclean one on the third and seventh days. He is to purify himself on the seventh day, and on the seventh day he is to wash his clothes and bathe himself in water, and at evening he will be clean.

20However, that man who is unclean but does not purify himself will be cut off from the community. He has defiled the Sanctuary of Adonai, since the cleansing water was not sprinkled on him. He is unclean.

21This will be a permanent ordinance for them. The one sprinkling the cleansing water is also to wash his clothes, and anyone touching the cleansing water will be unclean until evening.