This is another article in the chapter Enormities from the classical manual on Sharia called Reliance of the Traveller. The articles are posted one by one in the order they are given in the book.
p49.0 ARMED INSURRECTION AND CONSIDERING MUSLIMS UNBELIEVERS
(A: The early Kharijite sect committed these transgressions.)
p49.1 Allah Most High says:
(1) “Do not commit transgressions; surely Allah loves not the transgressors” (Koran 2: 190).
(2) “Whoever disobeys Allah and His messenger has gone manifestly astray” (Koran 33:36).
p49.2 The Prophet (Allah bless him and give him peace) said,
“If someone says to his Muslim brother, ‘You unbeliever,’ one of them deserves the name.”