Verse 23. - Ye shall make it go through the fire. This was an addition to the general law of lustration in chapter 19 founded on the obvious fact that water does not cleanse metals, while fire does. The spoils of the Midianites required purification, not only as being tainted with death, but as having been heathen property.

31:19-24 The Israelites had to purify themselves according to the law, and to abide without the camp seven days, though they had not contracted any moral guilt, the war being just and lawful, and commanded by God. Thus God would preserve in their minds a dread and detestation of shedding blood. The spoil had been used by Midianites, and being now come into the possession of Israelites, it was fit that it should be purified.Every thing that may abide the fire, ye shall make it go through the fire,.... Either through the smoke of the fire, and so be purified by suffumigation; or be put into the fire itself, where though they might be melted as the above things, yet not consumed as raiment, and vessels of skins, goats' hair, and wood, would be:

and it shall be clean; accounted so:

nevertheless, it shall be purified with the water of separation; with the water mixed with the ashes of the red heifer burnt, and sprinkled on it; see Numbers 19:9.

and all that abideth not the fire; without being consumed, as whatsoever is of wood, &c.

ye shall make go through the water; dip them in it, and rinse them there with a quantity sufficient; which the Targum of Jonathan says is forty seahs of water.