Elsewhere in the book “Reliance of the Traveler” it is stated that rules concerning slavery in Islam will not be discussed, since slavery has been abolished everywhere. We want to point out, Islam did NOT abolish slavery, and the rules concerning slavery are still known and ready to be used at any time. Mohammad himself enslaved people, though he also encouraged releasing slaves as a good deed. It’s like the bank robber who gets rewarded for bringing back some of the money he stole.
On the left, one of the rules concerning slavery in Islam is given, namely that the marriage of a woman is cancelled after being enslaved. In practice, Jihadists used women who were caught in Jihad, as sex slaves. This is also allowed in the Quran in this verse:
4.24. And all married women except those whom your right hands possess (this is) Allah's ordinance to you, and lawful for you are (all women) besides those, provided that you seek (them) with your property, taking (them) in marriage not committing fornication. Then as to those whom you profit by, give them their dowries as appointed; and there is no blame on you about what you mutually agree after what is appointed; surely Allah is Knowing, Wise.
The context of this verse is illustrated by a reliable hadith reported by Muslim, Muslim, Book 008, Number 3432:
Abu Sa'id al-Khudri (may Allah be pleased with him) reported that at the Battle of Hanain Allah's Messenger (may peace be upon him) sent an army to Autas and encountered the enemy and fought with them. Having overcome them and taken them captives, the Companions of Allah's Messenger (may peace be upon him) seemed to refrain from having intercourse with captive women because of their husbands being polytheists. Then Allah,
Most High, sent down regarding that:" And women already married, except those whom your right hands possess (iv. 24)" (i. e. they were lawful for them when their 'Idda period came to an end.