THE holy book is clear about what to do when you capture a city: “Put to the sword all the men in it”. As for the women and children, “You may take these as plunder for yourselves.” This is pretty much the advice that the fighters of Islamic State (IS) seem to have followed in the Sinjar area of northern Iraq, peopled largely by members of the Yazidi faith, that the jihadists seized last month. Reports by the UN and independent human-rights groups suggest that the invaders executed hundreds of Yazidi men and kidnapped as many as 2,000 women and children.

Any doubt as to the fate of these captives was dispelled by the latest issue of IS’s glossy English-language online magazine, Dabiq. An article titled “The Revival of Slavery Before the Hour” details religious justifications for reintroducing a practice that ended in all but a few Muslim countries more than a century ago. It claims not only that the Koran, the sayings of the prophet and traditional Islamic law all endorse the enslavement of infidel women captured in wartime, but that the abandonment of this right has caused sin to spread; men are easily tempted to debauchery when denied this “legal” alternative to marriage.

Better yet, the article grimly enthuses, the prophet himself foretold that one of the signs of the Hour—the end of the world—was when “the slave girl gives birth to her master.” This obviously means that concubines are needed to breed soldiers for jihad. Therefore, explains the writer, the victorious warriors of Sinjar divided the Yazidi women and children among themselves, “after one fifth of the slaves were transferred to the Islamic State’s authority as khums”, ie, the share of booty surrendered to early Muslim commanders.

The fastidious theologians of IS are right in some respects. Technically speaking, the syncretic Yazidi faith may be regarded by Islam as heathen, denying its adherents the protections that Christians and Jews—fellow “people of the book”—should enjoy. And it is true, too, that Islamic scripture, although vague in many matters, is specific about slavery, including such questions as whether sex is permitted. In recent times Muslim rebels in Sudan as well as in Nigeria have used such arcane justifications to excuse enforced concubinage.

Yet the fact is that, like members of most faiths, the vast majority of Muslims have pragmatic concerns about hyper-literal interpretations. Mainstream Muslim clerics, citing competing verses and traditions that praise the freeing of slaves as a virtuous act, often describe Islam’s abandonment of slavery as a sign of its adaptability to modern times. Besides, imagine if Christians and Jews still followed the letter of the Bible, which is, incidentally, the source of the passage at the top of this article. The verse (Deuteronomy 20:10-20) also prescribes that in case of capturing a city from the Hittites, Amorites, Canaanites, Perizzites, Hivites or Jebusites, the victors should “utterly destroy them” and “save alive nothing that breatheth”.