The method of installing the Khaleefah is through the process of bay‘ah. The power to rule by Islam is given by the Ummah to the Khaleefah. Authority belongs to the Ummah and it deputises the Khaleefah to enact the Shari‘ah. This is done through a contract between the Khaleefah and the Ummah. The Ummah must obey as long as the Khaleefah implements Islam on them.

The process of bay‘ah may occur after a general vote given by all the Muslims of the Islamic State or it may occur after a vote among the ahl al halli wal ‘aqd (people of influence and authority). Voting is merely a means to determine the choice of the Ummah, it does not substitute the bay‘ah. Non-Muslims, children, and Muslims residing out of the State do not have the right to vote. If all the Muslims of the Islamic State are voting then the bay‘ah al-in‘iqad (pledge of acceptance, by which he becomes Khaleefah) is given to the man elected. However, if the vote occurs through the representatives, then a bay‘ah al-in‘iqad is first given by the representatives, after which a second bay‘ah al-ta‘aa (pledge of obedience) is given by the Ummah to the person elected. The silence of the Ummah over the elected Khaleefah can be considered as the bay‘ah of obedience. It is through this bay‘ah process that a person attains his position as Khaleefah. The candidates for the position of Khaleefah may, in addition to self nomination, be chosen by the Majlis al-Ummah. It is from these candidates that the Ummah chooses for itself a ruler.

Once the appointment is made, the Ummah then has no right to dismiss the Khaleefah, as long as he upholds the Shari‘ah and fulfils the conditions to be a Khaleefah. Since the contract made between the Ummah and the Khaleefah is for the Khaleefah to rule upon them with Islam, the Ummah has no right to dissolve the contract, as long as he maintains his part of the contract. Therefore, a Khaleefah has no term of office. He remains the head of State, as long as he is able to uphold the contract or until he tenders his resignation.