Ibn `Umar (May Allah be pleased with them) reported: Messenger of Allah (PBUH) said, “One who withdraws his hand from obedience (to the Amir) will find no argument (in his defense) when he stands before Allah on the Day of Resurrection; and one who dies without having sworn allegiance will die the death of one belonging to the Days of Ignorance.” (Sahih muslim)
Another narration is: The Messenger of Allah (PBUH) said, “He who dies having defected from obedience (to the Amir) and discards his association with the main body of the (Muslim) community, dies the death of one belonging to the Days of Jahiliyyah.”
Anas (May Allah be pleased with him) reported: The Messenger of Allah (PBUH) said, “Hear and obey even if an Abyssinian slave whose head is like a raisin is placed in authority over you.” [Al-Bukhari].
`Abdullah bin Mas`ud (May Allah be pleased with him) reported: Messenger of Allah (PBUH) said, “There will be discrimination after my death and there will be other matters that you will disapprove.” He was asked: “O Messenger of Allah! What do you command us to do when we are encountered with such happenings?” He answered, “Give what is due from you and supplicate to Allah for your rights.’
Abu Hurairah (May Allah be pleased with him) reported: The Messenger of Allah (PBUH) said, “It is obligatory upon you to listen and obey the orders of the ruler in prosperity and adversity, whether you are willing or unwilling, or when someone is given undue preference to you.” [Muslim].
….and he should treat others as he wishes to be treated. He who swears allegiance to an Imam, he should give him the pledge in ratification and the sincerity of his heart. He should obey him to the best of his capacity. If another man comes forward as a claimant (when one has already been installed), behead the second.” [Sahih Muslim].
Wa’il bin Hujr (May Allah be pleased with him) reported: Salamah bin Yazid Al-Ju`f (May Allah be pleased with him) asked Messenger of Allah (PBUH): “O Prophet of Allah! Tell us, what you command us to do if there arises over us rulers who demand of us what is due to them and refuse us what is due to us.” Messenger of Allah (PBUH) turned away from him, but he repeated the same question. Thereupon Messenger of Allah (PBUH) said, “Listen to them and obey them. They are responsible for their obligations and you are accountable for yours.”[Sahih muslim]
Abu Hurairah (May Allah be pleased with him) reported: Messenger of Allah (PBUH) said, “Whosoever obeys me, obeys Allah; and he who disobeys me, disobeys Allah; and whosoever obeys the Amir (leader), in fact, obeys me; and he who disobeys the Amir, in fact, disobeys me.” [al-Bukhari and Muslim].
Ibn `Abbas (May Allah be pleased with them) reported: Messenger of Allah (PBUH) said, “If a person notices in his ruler what he dislikes, he should show patience because he who departs from the (Muslim) community a cubit, dies like those who died in the Days of Ignorance.” [Al-Bukhari and Muslim].
673. Abu Bakrah (May Allah be pleased with him) reported: I heard Messenger of Allah (PBUH) saying, “He who insults the rulers Allah will insult him.” [At-Tirmidhi].
And in our time, perhaps they will label the one who holds the [obligation] of hearing and obeying those in authority in whatever is other than disobedience to be a [paid] worker, a compromiser or a simpleton. You will see them reviling the one in authority over them, publicising his faults from the pulpits and in their gatherings, and the Messenger of Allaah (sallallaahu alayhi wasallam) says,”Whoever wishes to advices the ruler with a matter, then let him not proclaim it openly, but let him take him by the hand, take him into seclusion [and advise him], so if he accepts it from him [then so be it], and if not, then he has fulfilled that which is upon him.” Reported by Ahmad (3/404) from the hadeeth of Iyaad bin Ghunm (radiallaahu anhu) and it was also reported by Ibn Abi Aasim in “as-by Ibn Abi Aasim in “as-Sunnah” (2/522)
And in the hadeeth of Ubaadah bin as-Saamit (radiallaahu anhu) in the Two Saheehs, “Unless you see clear kufr for which you have a proof from Allaah”, and this was [in response to] the question of the Companions and their seeking permission to fight the oppressive rulers.