A--- Allah the Almighty says: {O you who believe! Obey Allah and obey the Messenger (Muhammad (Peace be upon him)), and those of you (Muslims) who are in authority. (And) if you differ in anything amongst yourselves, refer it to Allah and His Messenger ((Peace be upon him)), if you believe in Allah and in the Last Day.

That is better and more suitable for final determination}. (AnNisa', 59)

Narrated Anas Ibn Malik (May Allah be pleased with him): Allah's Messenger (Peace be upon him) says: "You should listen to and obey your ruler even if he was an Ethiopian (black) slave whose head looks like a raisin. " (Sahih Bukhari)

Narrated Ibn 'Abbas (May Allah be pleased with him): The Prophet (Peace be upon him) says: "Whoever notices something which he dislikes done by his ruler, then he should be patient, for whoever becomes separate from the company of the Muslims even for a span and then dies, he will die as those who died in the Pre-Islamic period of Ignorance (as rebellious sinners).”( Bukhari and Muslim)

'Ubadah Ibn As-Samit (May Allah be pleased with him) said: "The Prophet (Peace be upon him) called us and we gave him the Pledge of allegiance for Islam, and among the conditions on which he took the Pledge from us, was that we were to listen and obey (the orders) both at the time when we were active and at the time when we were tired, and at our difficult time and at our ease and to be obedient to the ruler and give him his right even if he did not give us our right, and not to fight against him unless we noticed him having open Kufr (disbelief) for which we would have a proof with us from Allah. "( Bukhari and Muslim)