Sahih Muslim Book 20, Hadith Number 4531.

Chapter : Obedience to the ruler is forbidden in matters sinful, but is otherwise obligatory.

Another version of the tradition does not qualify the slave with the epithets “maimed,” “an Abyssinian” but makes the addition: “I have heard the Holy Prophet (may peace be upon him) (say this) at Mina or ‘Arafat.”