Reference

Numbers 31:19

And do ye abide without the camp seven days: whosoever hath killed any person, and whosoever hath touched any slain, purify both yourselves and your captives on the third day, and on the seventh day.
17

Now therefore kill every male among the little ones, and kill every woman that hath known man by lying with him.

18

But all the women children, that have not known a man by lying with him, keep alive for yourselves.

19

And do ye abide without the camp seven days: whosoever hath killed any person, and whosoever hath touched any slain, purify both yourselves and your captives on the third day, and on the seventh day.

20

And purify all your raiment, and all that is made of skins, and all work of goats’ hair, and all things made of wood.

21

And Eleazar the priest said unto the men of war which went to the battle, This is the ordinance of the law which the Lord commanded Moses;

Counter-Arguments

The strongest case that this verse does not belong in this theme.

Seventh-Day Sabbath

The verse mentions "the seventh day" as a day for purification, not as a day of rest or a Sabbath. There is no explicit reference to the Sabbath or its associated practices.

Pre-Law Clean/Unclean Distinction

This verse is found in the book of Numbers, which describes events occurring after the giving of the Law at Sinai, thus it cannot be used as evidence for a "Pre-Law Clean/Unclean Distinction." The purification rituals described here are a direct consequence of the Mosaic Law concerning ritual impurity from death.

Symbolic / Spiritual Interpretation

This verse describes a literal ritual purification process for physical contact with death, with no explicit or implied symbolic meaning beyond the immediate requirement for ceremonial cleanliness.