Numbers 19:20-21

20‘But the man who is unclean and does not purify himself, that person shall be cut off from among the assembly, because he has defiled the sanctuary of the Lord. The water for purification has not been sprinkled on him; he is unclean.

21So it shall be a perpetual statute to them. He who sprinkles the water for impurity [on another] shall wash his clothes, and he who touches the water for impurity shall be unclean until evening.