24 On the seventh day you are to wash your clothes, and you will be clean. After that you may enter the camp.”
Numbers 31:24 Cross References - BSB
Leviticus 11:25
25 and whoever picks up one of their carcasses must wash his clothes, and he will be unclean until evening.
Leviticus 14:9
9 On the seventh day he must shave off all his hair—his head, his beard, his eyebrows, and the rest of his hair. He must wash his clothes and bathe himself with water, and he will be clean.
Leviticus 15:13
13 When the man has been cleansed from his discharge, he must count off seven days for his cleansing, wash his clothes, and bathe himself in fresh water, and he shall be clean.
Numbers 19:19
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.