Jihad in the Koran
In making war on the unbelievers, Allah reminded the believers not to let the booty distract them from their immediate goal which is shedding the blood of those who refuse to submit to His Will.
8:67 It is not up to any Prophet to take captives except after too much blood is shed (after the enemy is hard hit and subdued) in the land. You desire the fleeting goods of this world, but Allah desires the Hereafter, and Allah is Mighty, Wise.
A revealed truth confirming the inalienable right of a believer to the property, including the wife and kids of an unbeliever he has slaughtered.
8:68 But for a prior ordinance of Allah, you would have been afflicted on account of what you have taken (an ordinance which made it lawful for Muslims to take spoils and captives) by a terrible punishment.
The right of the believer to the property of a slain unbeliever is also confirmed in a saying of the Prophet where he makes terror a valid tactic in getting all to submit to the Will of Allah.
Narrated Abu Huraira:
Allah's Apostle said, "I have been sent with the shortest expressions bearing the widest meanings, and I have been made victorious with terror (cast in the hearts of the enemy), and while I was sleeping, the keys of the treasures of the world were brought to me and put in my hand."
What Allah will give the captives in whose hearts He finds some good is unclear.
8:70 O Prophet, tell those captives in your keeping: “If Allah knows of any good in your hearts, He will give you in return better than what has been taken from you and forgive you.” Allah is All-Forgiving, Merciful.
8:71 But if they wish to betray you, they have previously betrayed Allah, and so He subdued them. Allah is All-Knowing, Wise.
What God probably meant by "He will give you in return better" is a Muslim husband and forgive her for betraying Him if she chooses to become a Muslim herself, a necessary prerequisite to her getting a replacement spouse or her first husband.
2:221 Do not marry unbelieving women (polytheists) until they believe. A believing slave-girl is certainly better than an unbelieving woman, even if the latter pleases you. And do not give your women (believing women) in marriage to polytheists until they believe. A believing slave is certainly better than a polytheist even if the latter pleases you. Those (the polytheists) call to the Fire and Allah calls to Paradise and Forgiveness by His Leave; and He makes clear His Revelations to mankind so that they may be mindful.
A revealed truth within a hadith (both reinforcing each other) meant to reduce the resistance of the believers to raping their female captives, i.e., whom your right hands possess, in front of their husbands.
The Apostle of Allah (may peace be upon him) sent a military expedition to Awtas on the occasion of the battle of Hunain. They met their enemy and fought with them. They defeated them and took them captives.
Some of the Companions of the Apostle of Allah (may peace be upon him) were reluctant to have intercourse with the female captives in the presence of their husbands who were unbelievers. So Allah, the Exalted, sent down the Qur’anic verse: (4:24) "And all married women (are forbidden) unto you save those (captives) whom your right hands possess."
Abu Dawud 2.2150
Greetings and the Booty
4:86 And when you are greeted with a certain greeting, greet back with a better one or return it; for Allah keeps count of everything.
4:94 O believers, if you journey in the Way of Allah, be discerning and do not say to him who greets you: “You are not a believer”, seeking the fleeting goods of the present life. For with Allah are abundant gains. This is how you were before and Allah has been gracious to you; so discern well. Allah is indeed fully aware of what you do!
According to preeminent Koranic scholar and first recipient of the King Faisal International Award for his services to Islam and Islamic studies Abul A’la Moududi:
In the early days of Islam the greeting as-salam 'alaykum ('peace be on you') was a distinguishing symbol of the Muslims. When a Muslim greeted another Muslim with this expression it signified that he was a member of the same community from whom he need entertain no fear of hostility and towards whom, in return, he should not behave with hostility.
[This caused a problem] on the battlefield. Whenever a Muslim was in danger of being harmed inadvertently by other Muslims during the fighting, he resorted to either the Islamic greeting (as-salam 'alaykum) or the Islamic creed There is no god save Allah' (ili-Jl) in order to indicate that he was their brother-in-faith.
The Muslims, however, often suspected this to be merely a ruse of the enemy and therefore sometimes disregarded the utterance of the Islamic greeting or of the Islamic creed, and killed such people and seized their belongings as booty.
God solved the problem by revelation. The purport of the verse is that no one has the right summarily to judge those who profess to be Muslims, and assume them to be lying for fear of their lives… The error of letting an unbeliever go unpunished is preferable to that of killing a true believer.
Learn how to say the life-saving words correctly:
Narrated Ibn 'Umar:
The Prophet sent (an army unit under the command of) Khalid bin Al-Walid to fight against the tribe of Bani Jadhima and those people could not express themselves by saying, "Aslamna (we profess Islam)," but they said, "Saba'na! Saba'na!"
Khalid kept on killing some of them and taking some others as captives, and he gave a captive to everyone of us and ordered everyone of us to kill his captive...