Num 19:17-22 : 17 For the unclean person, they shall take some of the ashes from the burnt purification offering, and fresh water shall be added to them in a container.
18 Then a clean person shall take hyssop, dip it in the water, and sprinkle it on the tent, on all the vessels, on the people who were there, and on anyone who touched a bone, a slain person, a dead body, or a grave.
19 The clean person shall sprinkle the unclean on the third day and on the seventh day. On the seventh day, he shall purify him. Then the one being purified must wash his clothes and bathe in water, and he will be clean by evening.
20 But if someone is unclean and does not purify himself, that person shall be cut off from the assembly because he has defiled the sanctuary of the LORD. The water of purification has not been sprinkled on him; he is unclean.
21 This shall be a permanent statute for them. The one who sprinkles the water of purification must wash his clothes, and anyone who touches the water of purification will remain unclean until evening.
22 Anything that the unclean person touches will become unclean, and anyone who touches it will remain unclean until evening.