MSB(i)
19 The man who is ceremonially clean is to sprinkle the unclean person on the third day and on the seventh day. After he purifies the unclean person on the seventh day, the one being cleansed must wash his clothes and bathe in water, and that evening he will be clean.
20 But if a person who is unclean does not purify himself, he will 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.