Shaikh Abu Fareehaan Jamaal al-Haarithee (may Allaah preserve him) said:

Have you not seen that after their splitting [i.e. Khawaarij—Terrorists (ISIS, An-Nusrah and Daa-ish)] between themselves, they declared one another disbelievers and fought one another. Have you not seen that the Muslims are (now) in a state of fright and fear from these ones and those ones and they do not know who amongst them is upon truth!?