Rasulullah SAW has ordered the Muslims that they appoint a khalifah after he SAW death, which dibai'at with bai'at syar'iy to command the Muslims based on Kitabullah and Sunnah Rasulullah SAW. Upholding the Shari'ah of Allah, and jihad with the Muslims against the enemies of Allah
Rasulullah SAW said: "There is no Prophet after me, and there will be caliphs, and many (in number)." the Companions asked, "What do you command us? The Prophet SAW replied," Fill the first bai'at, and the first. And Allah will ask them what they lead. "(Narrated by Muslim) The Messenger of Allah (PBUH) has a will to the Muslims, lest there be any period without the caliph (who leads the Muslims) .If this happens, in the absence of a caliph , it is obligatory for the Muslims to try to appoint a new caliph, even if it leads to death
Sayings of the Prophet (s): "Whosoever shall die and shoulders not in favor of an Imam (caliph), then his death (as) dies (in the circumstances) jahiliyyah."
Rasulullah SAW also said: "If you witness a caliph, be obedient, although (he) hit your back, if there is no khalifah, there will be Chaos." (HR THABARANI
Allah Almighty has commanded (to us) to obey the Caliph. Allah says: "O you who say, obey Allah and obey the Messenger (His), and ulil amri among you." (AN NISA: 59)
The Muslims have been keeping the Rasulullah SAW's will for 13 centuries. During that time interval, the Muslims never witnessed a life without being led by a caliph who governs their affairs. When a caliph dies or is replaced, ahlul halli wal 'aqdi immediately seeks, selects, and determines the successor to the previous caliph. This continues in the days of Islam (at that time). Every time, the Muslims constantly witness the bai'at to the caliph on the basis of obedience. It began from the time of Khulafaur Rashidin until the period of the Caliphs of the 'Ottoman dynasty
In the history of the Muslims to this day, the Islamic government under the Islamic Khilafah institution was once led by 104 caliphs. They (khalifahs) consisted of five caliphs of khulafaur raasyidin, 14 caliphs of Umayyad dynasty, 18 caliphs of 'Abbasid dynasty, followed by Bani Buwaih 8 caliphs, and from Bani Saljuk 11 caliphs. From here the center of government was moved to Cairo, followed by 18 caliphs. After that the Caliph passed to the Bani 'Uthman. From Bani there are 30 caliphs. The people still know the names of the rashidin khulafaurs compared with others. Although they also do not forget the Caliphs' Umar bin 'Abd al-'Aziz, Harun al-rashid, Sultan' Abdul Majid, as well as khalifahs famous in history.