Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) narrated: "the Messenger of Allah (peace and blessings be upon him) ordered fighting against al-Nakithin (the oath-breakers), al-Qasitin (the oppressors) and al-Mariqin (those who pass out of the religion)."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 10017