The Purification of the Israelite Army after the Slaughter. The purification of warriors after a battle, practised in antiquity as by savage peoples to-day, was due, not to any desire for physical cleanliness, but to the dread of the mystery involved in spilt blood and in dead bodies: those who had been in contact with such were sources of danger to the community until ritually purified. The rules observed are those prescribed in Numbers 19:11 f.; but in addition it is here enjoined that everything that can stand fire shall be purified by fire and by the water of separation (Numbers 19:9), whereas for everything likely to suffer from fire ordinary washing shall suffice.
Numbers 31:19-24
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;
22 Only the gold, and the silver, the brass, the iron, the tin, and the lead,
23 Every thing that may abide the fire, ye shall make it go through the fire, and it shall be clean: nevertheless it shall be purified with the water of separation: and all that abideth not the fire ye shall make go through the water.
24 And ye shall wash your clothes on the seventh day, and ye shall be clean, and afterward ye shall come into the camp.