وقال عبد الله محمد الضعيف – أحد أئمة السلف – :
فَعَدُ الخوارج هم أخبت الخوارج
رواه أبو داود في مسائل أحمد ص ٢٧١ بسند صحيح
'Abdullah Bin Muhammad Ad Da'eef (rahimahullah) -one of the Imaams of the Salaf- said,
The Qa'ad (i.e. the Qa'adiyyah1) of the Khawaarij are the worst and most vile of the Khawaarij.
[Reported in the Masaail of Imaam Ahmad (rahimahullah) by Imaam Abu Dawud (rahimahullah) on pg. 271 with an authentic chain of narration.]
TN: The Qa'adiyyah are those from the Khawaarij who incite others to rebel, revolt, and commit acts of atrocity while they themselves do not take part in the actual fighting and/or “operations.” They are the worst of the Khawaarij because they are in fact the root and cause of these evil acts. Therefore, any "radical cleric" calling people to the methodology of the evil Khawaarij and inciting them to commit acts of terrorism is thus from the Qa'adiyyah and subsequently the worst of the Khawaarij.