There are several PROBLEMS and SOLUTIONS with a Muslim trying to use the Numbers 31 passage to prove anything. To prove what exactly? Typically of Muslims, you probably have not read about the broader context of the passage. The passage reads as follows:
“Moses was angry with the officers of the army—the commanders of thousands and commanders of hundreds—who returned from the battle. “Have you allowed all the women to live?” he asked them. “THEY (the women) WERE THE ONES WHO FOLLOWED BALAAM’S ADVICE AND ENTICED THE ISRAELITES TO BE UNFAITHFUL TO THE LORD IN THE PEOR INCIDENT, SO THAT A PLAGUE STRUCK THE LORD’S PEOPLE. Now kill all the boys. And kill every woman who has slept with a man, but save for yourselves every girl who has never slept with a man.”
Numbers 31:14-18
The Baal Poer incident is when the Moabite women seduced the Israel man into idolatry and sexual sin. As a result God judged the man of Israel by a plague (14 700 Israelite men died from the plague)
PROBLEM NUMBER 1
Allah claims to be the God of the Torah (the book of Numbers is one of the 5 books of the Torah) which the Qur’an confirms as Allah’s word which, as of the 7th century, ‘they had with them’, ‘still remains’ and Jews must judge themselves by the Torah otherwise they would be non believers if they did not follow the Torah:
Sura 7:156-157:
“And I will write down (my mercy) for those who are righteous and give alms and who believe in our signs; who follow the apostle, the unlettered prophet, whom they find written in the Torah and the Gospel THAT IS WITH THEM.”
5:43. And how should they appoint you their judge whilst they HAVE WITH THEM the Torah which contains the law (and judgment) of Allâh. Yet they turn their backs even after that (you judge between them). And such people ARE NOT TRUE BELIEVERS (neither in the Qur’ân nor in the Torah).
Sura 5:71:
“Say, O People of the Book! You are not (founded) on anything UNTIL you PERFORM the TORAH and the GOSPEL, and what was revealed to you from your Lord.”
The Qur’an further confirms that the Torah and Gospels were not corrupted nor disappeared as late as the 7th century. They still EXISTED.
3:3. He has revealed to you gradually this perfect Book (-the Qur’ân) which meets all your requirements, fulfilling that (prophecies in the Scriptures) which PRECEDED it AND WHICH STILL REMAIN. He revealed the Torah and the Evangel”
So why are you having a problem with a passage of scripture which your god claims to have revealed and which Jews must believe in?
PROBLEM 2.
It is God who has instructed Moses to carry out the attack. Doesn’t Allah of the Qur’an claim (QS 29:46) to be the God of the Torah? Muslims really do have cognitive dissonance issues!
PROBLEM 3.
It is Moses who is giving instructions to the commanders to kill the women and the boys. Don’t Muslim scholars claim that Muhammad is the prophet like Moses?
SOLUTION 1.
God told Moses, “Take vengeance on the Midianites for the Israelites” (Numbers 31:1). The Israelites obediently armed themselves and attacked the Midianites, killing the men (verse 7). Also, “the Israelites captured the Midianite women and children and took all the Midianite herds, flocks and goods as plunder” (verse 9). When the troops returned to Moses, he was angry that they had not fully carried out the Lord’s vengeance (verse 14; cf. verse 3). The MIDIANITE WOMEN WERE THOSE WHO HAD CAUSED ISRAEL TO SIN AT BAAL PEOR (see Numbers 25). So Moses commanded that the women be killed, and also “kill all the boys” (Numbers 31:17).
SOLUTION 2
When we look at the command to kill the male Midianite children, there are two perspectives we might take. One is the more understandably temporal. During the timeframe in question, tribal warfare was rampant. It was highly likely that the male Midianite children would grow up and seek revenge for their fathers and grandfathers against Israel.
SOLUTION 3A
Further, the utterly disgusting depravity in which these Midianite boys had been raised is well documented. Regular behaviors among the Midianites included child sacrifice, cult prostitution, and bestiality. The divine prohibition of these acts was codified, and the acts were known to the Israelites (Leviticus 18:21, 23–24). Male survivors carrying on the lineage of this culture would have been a future problem for Israel.
SOLUTION 3B
The other perspective we should consider is the DIVINE. Now, we cannot know the mind of God or comprehend the depths of His wisdom (Isaiah 55:8–9). But we can know that, given the depravity of the Midianites, God’s command to kill the Midianite boys might have been an act of divine mercy. In His perfect knowledge—including His knowledge of what would happen in the lives of those young Midianites, had they lived—it’s possible that God brought them to Himself before they had the opportunity of choosing to reject Him. It is highly possible that, had these males grown to maturity, they would have embraced the wanton rebellion and idolatry of their fathers. From God’s perspective, it may have been better for them to die at a young age than to endure a life of depravity.
SOLUTION 4
In all this, we must remember that God is goodness. The very nature of God is such that He cannot do evil. “The LORD is righteous in all his ways” (Psalm 145:17). This is the point by which we must reconcile passages such as Numbers 31:17 with the likes of John 3:16.
Also, we are incorrect when we start embracing notions like “if I were God, I certainly would not have done that.” God does not see human events as we do; He sees them as only God can. Thus, we have no basis by which to say that God would not have a humanly understandable, morally sufficient reason for commanding the death of children during the conquest of Canaan.
FINALLY, you have been deceived. You are probably right to be critical of God’s decision in the book of Numbers because you probably know that your 7th century god, Allah of the Qur’an is not the true God of Abraham, Isaac and Jacob. Frankly, Allah is a false god, probably Satan himself, who falsely associates himself with the Torah and Gospels inorder to create a past and credibility for himself and Islam, his false religion. Ironically, by criticizing the Torah and Gospels, Muslims are unknowingly rightly confining Allah of the Qur’an to a 7th century false god who has no written historical records or oral tradition before 610 (except perhaps as one of the 360 pagan gods of the abominable Kaaba and idolatrous Hajr e aswad).