The Amalekites (cf. Deut. 25:17-19) and the Midianites
posed so serious a threat to Israel that their cases stand out. The former endangered Israel's existence. That latter posed a particularly devious strategy to degrade Israel's spiritual and moral uprightness.
More than twenty thousand Israelite
lives [/b] had been lost because of succumbing to the fornication and idolatry schemed by the Midianites to corrupt Israel (Num. 25:1-2;31:16)
. This tactic was invented by a Gentile prophet of God, Balaam
who had been overcome by the temptation of greed to attempt to pronounce a divine curse on Israel. When he could not he concocted an terrible trick to corrupt Israel through sexual lust and idolatry and seduction from Midianite
The heinous deviousness and the loss of over twenty thousand Israelites God commanded to be avenged.
"Then Jehovah spoke to Moses, saying, Thoroughly avenge the children of Israel on the Midianites; afterwards you will be gathered to your people." (Num.31:1,2)
I think that the killing of every woman who had slept with a man has Numbers 25
as its backround. The willing Midianite
woman formed a seductive army of temptresses to lead Israelite men into orgiastic adultery and worship of the Baal.
The females who were virgins must have been the ones who had not participated in the plan. Some people assume that the keeping the female virgins alive for the men must mean that they were raped. If they had been that would have been violation of what God had ordained about female prisoners of war. A protocol forbidding recreational sex with woman captives of war had been instituted by God.
forbidding rape of female POWs.
"When you go out to fight against your enemies and Jehovah your God delivers them into your hands and you take them captive,
And you see a beautiful woman among the captives and desire her and would take her to yourself AS A WIFE;
You shall bring her within your house, and she shave her head, trim her nails,
And take her clothes of captivity away from her. And she shall dwell in your house AND MOURN HER FATHER AND MOTHER FOR A FULL MONTH.
And AFTERWARDS... you shall go into unto her and BE HER HUSBAND, and she shall be A WIFE TO YOU.
And if after a time you do not delight in her, you shall let her go wherever she wishes. But you must not sell her for money; you shall not deal with her as a slave, because you have humbled her." (Deut. 21:10-14)
So as less than idle is the result of being a woman captive to ancient Israelite army rape or recreational sex was forbidden by God. She was not to be a sex slave.
They were not free to grab and rape any girl. The women spared had not participated in the mass seduction.
As for the males which were all to be slain, the preemptive avoidance of any future Midianite
army formation must have been the reason. That it was harsh can hardly be denied. We should remember that the Israelite males had been also been put to death who had participated in the seduction.
Interestingly, latter the Israelite kings, with such a conquest backround, still had a reputation of being merciful among some of their latter enemies (1 Kings 20:21)
JPS Tanakh 1917
And his servants said unto him: 'Behold now, we have heard that the kings of the house of Israel are merciful kings; let us, we pray thee, put sackcloth on our loins, and ropes upon our heads, and go out to the king of Israel; peradventure he will save thy life.'