Numbers 19:22

The clean person shall sprinkle on the unclean on the third day, and on the seventh day. On the seventh day, he shall purify him. He shall wash his clothes and bathe himself in water, and shall be clean at evening.

But the man who shall be unclean, and shall not purify himself, that soul shall be cut off from among the assembly, because he has defiled the sanctuary of the LORD. The water for impurity has not been sprinkled on him. He is unclean.

It shall be a perpetual statute to them. He who sprinkles the water for impurity shall wash his clothes, and he who touches the water for impurity shall be unclean until evening.