From Syria to Iraq
Just a year ago abbreviation of ISIL was clear just for those who followed tragic events in Syria with professional interest. Today ISIL makes itself more .... popular with siege of extensive pieces of Iraq territory and with declaration of Islamic State (Caliphate). 
A real glory of ISIL as a jihadist organization became “Syrian stage”, where militants of group were fighting under the rule of “Jabhat an-Nusra”, having press of “Free Syrian Army” which supported by the West. During the Iraq campaign group was closely connected with "Al-Qaeda" and was called: "Al-Qaeda in Iraq". Group was made from various fighting Sunni radical groups which were struggled against American troops, governmental forces, and also against Shiite militants. 
Tactics of militant group wasn't limited to usual guerrilla war against invaders. Fighters arranged bloody acts of terrorism with suicide bombers and the mined cars. Group renamed more than once — until it didn't receive the name "Islamic State of Iraq" and then, when jihadists interfered the Syrian civil war, there was a new name with addition of "Levant" (or "the countries Sham"). ISIS proclaimed the purpose of caliphate establishment in the territory of Iraq and Syria and other countries. . The majority of Islamic groups draw that the real Islam existed only at the time of "Golden Age" when there was a state which was established by the prophet Muhammed.
Who are they - fighters of the Islamic state of Iraq and Levant?
- It includes from 12.000 to 15.000 well armed fighters.
- Organization leading by Abu Bakr al Baghdadi, who considers a talented military strategist. He headed a cell of "Al-Qaeda" from which then ISIS was created. It is considered that the group used the opposition which has arisen between the government of Iraq and Sunni minority which considered that the Prime Minister Nuri al-Maliki, the Shiite on religion, usurped the power.
The Prime Minister al-Maliki suggested to introduce the state of emergency granting to him of additional powers. Fully aware of situation demands strong measures in order to save the national security inside of the country. What kind of measures – is also unclear. 
The main enemies of ISIS declared Shiites who are forming the majority of the population in Iraq. It is known that during Iraqi war Sunnites battled against the USA more stubbornly as Hussein was a Sunnite and patronized to all brothers in faith.
According to the main analyses of the US authorities, nobody in Washington is going to fight against ISIS seriously. Let's look at the facts: externally everything is organized as "expansion of Islamists", they threaten the West and propagandize idea of the Caliphate by giving statements and actually, by efforts created a corridor from which groups of the Syrian rebels already started receiving the weapon paid by Middle Eastern sponsors.
By this step the Iranian opportunities giving help to Bashar Assad were reduced. By the next and third step, rebels blocked supply of oil to Syria, ISIS militants were succeeded to took control over two main oil pipelines: one supplies Syria, another – goes to the Turkish Jeihan.
As a result - the first is blocked that provoked interruptions in electricity in Syria but the second - normally functions by means of the ARAMKO oil company (Saudi Arabia), delivering oil of an autonomy of the Iraq Kurdistan to Israel.
It is also interesting that the position of Iran concerning terrorist groups in the Middle East. Iran is certainly ready to give help to the legitimate government of Iraq, but – only at the level of adviser and instructors. The big chaos is developing in the Middle East. Notice, Tel Aviv is not strongly concerned by the events in nearby of its borders, and it means much more. 
1) Vesti.az: “ЭКСТРЕМИСТСКАЯ ГРУППИРОВКА ИГИЛ СОЗДАЛА ЯЧЕЙКУ В ИОРДАНИИ”. URL: http://vesti.az/news/207751
2) Боевики-сунниты создают единый халифат Ирака и Сирии. URL: http://urfo.org/inworld/502504.html
3) Deutsche Welle: “ISIS, oil and war.” URL: http://www.dw.de/isis-oil-and-war/a-17760035
4) Global Research: “The strange case of Iraq’s PM Nuri al-Maliki”. URL: http://www.globalresearch.ca/the-strange-case-of-iraqs-prime-minister-nouri-al-maliki-against-the-backdrop-of-the-war-against-the-islamic-state-is/5389805
5) The Shia Post: “Allah has not ordered us to fight against Israel”. URL: http://en.shiapost.com/2014/07/12/allah-has-not-ordred-us-to-fight-against-israel/
6) The Hufftington Post: Ronald Tiersky “What does it mean for Israel”. URL: http://www.huffingtonpost.com/ronald-tiersky/isis-what-does-it-mean-fo_b_5489756.html