Abide without the camp seven days According to the law, Leviticus 15:13. Purify yourselves With the water of sprinkling, Numbers 19:9. Your raiment Namely, your spoil and prey. All work All which had contracted some ceremonial uncleanness, either from the dead bodies which wore them, or the tents or houses where they were, in which such dead bodies lay, or from the touch of the Israelitish soldiers, who were legally defiled by the slaughters they made.
Related Commentaries of Numbers 31:19
Numbers 31:19-20
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.