Numbers 19:19-20

19On the third and seventh days the person who is ceremonially clean must sprinkle the water on those who are defiled. Then on the seventh day the people being cleansed must wash their clothes and bathe themselves, and that evening they will be cleansed of their defilement.

20“But those who become defiled and do not purify themselves will be cut off from the community, for they have defiled the sanctuary of the Lord. Since the water of purification has not been sprinkled on them, they remain defiled.