Summary of main points: Beware of these factions who are upon the Manhaj of the Kharijites, ISIS or al-Nusrah, all of them have come from amongst the Muslim Brotherhood. These factions declare Muslims to be disbelievers and make lawful the killing of Muslims. The violate their blood and their property. They are upon astray methodologies. One must keep away from them. You must return to the Scholars whom the Muslims have been ordered to refer back to (21:7, 24,83). They must leave the methodologies of the Kharijites. Their original founder is the one who suspected the Messenger (sallallaahu alayhi wasallam) and said to him "Be just", these Kharijites are the ones who killed Uthmaan (radiyallaahu anhu). They are the ones who killed Alee (radiyallaahu anhu). They are the ones who killed Khabbaab bin al-Araat (radiyallaahu anhu). They killed the best of the ummah from the rightly guided Caliphs and the noble Companions. So I warn the brothers from joining them or any misguided sects which are based upon Takfir. These groups are supported by those with enmity to Islam from amongst the Jews, Christians and the Masons in order to disfigure the picture of Islaam. They violate blood which is inviolable, women, children. Listen to the speech of Abdullah bin Saba' who made an outward display of Islam, "Make a display of enjoining good and forbidding evil until the hearts incline towards you then direct them to the intended affair" - this is the methodology of this one and the Kharijites. Imaam Ibn Baz held the view of Takfir of the Kharijites, as the Prophet (sallallaahu alayhi wasallam) said about them, "They exit from the religion like the arrow leaves the bow..." So beware O Muslims... from these misguided groups, ISIS and Nusrah, but learn the methodology of the Prophet (sallallaahu alayhi wasallam) and stick to his Sunnah. This is what you will be asked in the grave, about your Islam and about your Prophet. If you were upon Tawhid, you will be granted success and if you were making ittibaa (following) the Prophet's Sunnah, you will be granted success (in answering truthfully). You will be asked how you responded to the Messengers. These groups have been created and supported to disfigure the picture of Islaam, so woe be to them from Allaah, who violate the sanctities, spread turmoil, insecurity, fear and disfigure the picture of Islam... The Messenger (sallallaahu alayhi wasallam) even prohibited from carrying weapons in a manner that might harm others. Whoever killed a believing soul deliberately, his recompense will be Hellfire, remaining therein forever... (4:93).