The Imam Whom Obedience Is Obligatory and How the Imamate Is Established

Question:
This questioner says: He says: The imam whom it is necessary to obey, the imam to whom obedience is required, is the imam upon whom the entire ummah (Muslim community) agrees. What is your opinion on this?

Answer:
This is an error; it is not the case in absolute terms. The imamate is established by one of several matters: either the ummah agrees and chooses him, as they chose Abu Bakr (may Allah be pleased with him); or the imam chosen by the ummah chooses a successor who will take over after him, as Abu Bakr chose 'Umar ibn al-Khattab (may Allah be pleased with him), and the ummah obeyed him.
Or the one in authority seizes power by force, and he is a Muslim; if he is a Muslim who seizes power by force and takes authority, he is to be obeyed, as happened with 'Abd al-Malik ibn Marwan, which the scholars mentioned in the issue of establishing authority. Or he is established by the pledge of allegiance of the people of authority and decision (ahl al-hall wa al-'aqd); it is not necessary for everyone to agree, the people of authority and decision are sufficient, like those who pledged allegiance to Abu Bakr al-Siddiq; his obedience became obligatory upon all people, even if they were not present and did not pledge allegiance, the people of authority and decision are sufficient. Or the one in authority chooses a successor, and the obedience of the one who comes after him becomes obligatory, because he has the authority to do so, as Abu Bakr chose 'Umar ibn al-Khattab (may Allah be pleased with him). Or he seizes power by force, and he is a Muslim; if he seizes power and no one remains to contest him, his obedience becomes obligatory to unite the word, as happened in the era of 'Abd al-Malik ibn Marwan. Yes, it is necessary for a person to understand these matters, not to take the statements of those who disagree, or to rely on his own idea and opinion without referring to the words of the scholars. Yes.