Numbers 19:17-18

17“‘For a ceremonially unclean person you must take some of the ashes of the heifer burnt for purification from sin and pour fresh running water over them in a vessel.

18Then a ceremonially clean person must take hyssop, dip it in the water, and sprinkle it on the tent, on all its furnishings, and on the people who were there, or on the one who touched a bone, or one killed, or one who died, or a grave.