Islamic State: Grounding its Violence in True Islam?

Islamist Sword
Dabiq Magazine
MEMRI

A recent article in issue VII of the Islamic State (ISIS) English-language magazine Dabiq rejects claims that Islam is a peaceful religion and argues that it bases itself on the sword (February 12, 2015). A few quotes are provided below:

"There is a slogan repeated continuously by apologetic 'du'at' [callers for Islam] when flirting with the West and that is their statement: 'Islam is the religion of peace,' and they mean pacifism by the word peace. They have repeated this slogan so much to the extent that some of them alleged that Islam calls [for] permanent peace with kufr [unbelief] and the kafirin (unbelievers). How far is their claim from the truth, for Allah has revealed Islam to be the religion of the sword, and the evidence for this is so profuse that only a zindiq (heretic) would argue otherwise.

As evidence of Islam's righteous antipathy towards non-Muslims, ISIS cites words from the fourth caliph:

"'Ali Ibn Abi Talib . . . said, 'Allah's Messenger [i.e., Muhammad] . . . was sent with four swords: a sword for the mushrikin [polytheists] . . . a sword for Ahlul-Kitab [people of the book, i.e. Jews and Christians] . . . and a sword for the bughat [aggressors] . . . He also revealed the sword against the apostates . . . [Allah] also described what should be struck with the sword, {Remember when your Lord revealed to the angels, 'I am with you, so strengthen those who have believed. I will cast terror into the hearts of those who disbelieved, so strike [them] upon the necks and strike from them every fingertip'} [Koran 8:12]. [He] also said, {So when you meet those who disbelieve, strike their necks until, when you have inflicted slaughter upon them, then secure their bonds, and either [confer] favor afterwards or ransom [them] until the war lays down its burdens} [Koran 47:4]. His Messenger . . . also described the sword as the salvation from evil and fitnah [strife]. [He] also described the sword as being the key to Jannah [paradise] . . . He also declared that his worldly provision was placed for him in the shade of his spear and that the best livelihood for the Muslim in the future is what he takes with his sword from the kafir [unbelieving] enemy.

ISIS thus calls for undying enmity toward just about everyone who doesn't follow the Islamic State's version of Islam.

"So how can the zanadiqah (heretics) or even those who blindly follow them - [George W.] Bush, [Barack] Obama, and [John] Kerry - obstinately claim that 'Islam is a religion of peace,' meaning pacifism? One of the biggest shubuhat [misconceptions] propagated by the heretics is the linguistic root for the word Islam. They claim it comes from the word salam (peace), when in actuality it comes from words meaning submission [Istislam] and sincerity [Salamah] sharing the same consonant root . . . "It is clear then that salam (peace) is not the basis of the word Islam, although it shares the same consonant root (s-l-m) and is one of the outcomes of the religion's sword, as the sword will continue to be drawn, raised, and swung until 'Isa (Jesus - peace be upon him) kills the Dajjal (the Antichrist) and abolishes the jizyah [poll tax]. Thereafter, kufr and its tyranny will be destroyed; Islam and its justice will prevail on the entire Earth . . . But until then, parties of kafirin will continue to be struck down by the unsheathed sword of Islam - except for those who enter into iman (Islamic faith) or aman (a guarantee of safety) - for there will always be a party of Muslims fighting parties of kafirin until there is no more fitnah and the religion is completely for Allah alone."

The Islamic State is pretty clear about its ultimate goal, conquest of the entire earth for its God, Allah. I'm no linguist, but I've long been skeptical of the argument that the word "Islam" is derived from the word for "peace" (salam), so I'm interested in the linguistic claims made here.

Is ISIS right and its Islamic State a true expression of Islam?