Mihnaf bin Sulaym narrates: We came to Sayyiduna Abu Ayyub al-Ansari (may Allah be pleased with him) while he was feeding his horses at a place called Sa'naba, and we spent the midday rest with him. I said to him: O Abu Ayyub, you fought the polytheists alongside the Messenger of Allah (peace and blessings be upon him), and now you have come to fight the Muslims? He said: The Messenger of Allah (peace and blessings be upon him) ordered me to fight three groups: the Nakithin (the oath-breakers), the Qasitin (the unjust) and the Mariqin (those who pass out of the religion). I have fought the Nakithin, and I have fought the Qasitin, and now, if Allah wills, I will fight the Mariqin; (they will be) in the heights, on the roads and at al-Nahrawanat, and I do not know who they are.
Hadith Referenceالمعجم الكبير للطبراني / باب الخاء / 4034