From Christian Today:
Islamic militant terrorists ISIS is giving non-muslims in Iraq three options: leave, convert or die.
ISIS has reportedly been giving the ultimatum since the group took over Mosul, the capital of the Nineveh providence in northern Iraq, in June.
The group also threatened to impose a “special tax” on Iraqi Christians. Thousands of Christians left Mosul in July after the group gave the ultimatum saying that if they did comply there would be 'nothing for them but the sword."
These people (ISIS) believe that they are doing a holy thing in their actions. From the Quran (Sura At Taubah verses 29 -35)
29 Fight against such of those who have been given the Scripture as believe not in Allah nor the Last Day, and forbid not that which Allah hath forbidden by His messenger, and follow not the Religion of Truth, until they pay the tribute readily, being brought low.
30 And the Jews say: Ezra is the son of Allah, and the Christians say: The Messiah is the son of Allah. That is their saying with their mouths. They imitate the saying of those who disbelieved of old. Allah (Himself) fighteth against them. How perverse are they!
31 They have taken as lords beside Allah their rabbis and their monks and the Messiah son of Mary, when they were bidden to worship only One God. There is no God save Him. Be He Glorified from all that they ascribe as partner (unto Him)!
32 Fain would they put out the light of Allah with their mouths, but Allah disdaineth (aught) save that He shall perfect His light, however much the disbelievers are averse.
33 He it is Who hath sent His messenger with the guidance and the Religion of Truth, that He may cause it to prevail over all religion, however much the idolaters may be averse.
34 **O ye who believe! Lo! many of the (Jewish) rabbis and the (Christian) monks devour the wealth of mankind wantonly and debar (men) from the way of Allah. **They who hoard up gold and silver and spend it not in the way of Allah, unto them give tidings (O Muhammad) of a painful doom,
35 On the day when it will (all) be heated in the fire of hell, and their foreheads and their flanks and their backs will be branded therewith (and it will be said unto them): Here is that which ye hoarded for yourselves. Now taste of what ye used to hoard.
(I am not saying that this is “authentic Islam” – but this sure appears to be an interpretation of Islam to which these folks subscribe)