Game da ƙa'ida ta uku, cewa kafa Khalifa guda ɗaya wajibi ne ga dukkan Musulmi, hadisi mai zuwa ya tabbatar da hakan. Muslim ya ruwaito daga Nafi'i cewa ya ce: 'Abdullahi ɗan 'Umar ya ce mini: Na ji Manzon Allah ﷺ yana cewa:

As for the third principle, that the establishment of one Khaleefah is an obligation on all Muslims, the following Hadith has confirmed this. Muslim narrated from Naf ’i that he said: ‘Abdullah Ibnu ‘Umar said to me: I heard the Messenger of Allah (pbuh) say:

"Duk wanda ya cire hannunsa daga biyayya ga Allah, zai gamu da Allah (SWT) a Ranar Tashin Alƙiyama ba tare da yana da hujja da zai nuna wa kansa ba; kuma wanda ya mutu alhali babu baiwar biyayya a wuyansa, to ya mutu mutuwar zamanin Jahiliyya (jahilci)." A cikin wannan Hadisi, Manzon Allah ﷺ ya wajabta ga kowane Musulmi ya kasance yana da baiwar biyayya, watau Bai'ah ga Khalifa a wuyansa, amma bai wajabta ga kowane Musulmi ya bayar da Bai'ah ba. Wajibi shi ne kasancewar Bai'ah a wuyan kowane Musulmi, watau kasancewar Khalifa wanda yake da hakkin a yi masa Bai'ah a wuyan kowane Musulmi ta hanyar kasancewarsa. Kasancewar Khalifa ita ce al'amarin da ke haifar da Bai'ah a wuyan kowane Musulmi, ko Musulmin ya bayar da Bai'ah a zahiri ko bai bayar ba. Dangane da haɗin kan Khilafah da haramcin samun fiye da Khalifa guda ɗaya, wannan yana bisa abin da Muslim ya ruwaito daga Abu Sa'idi Al-Khudri daga Manzon Allah ﷺ cewa ya ce:

“Whoever takes off his hand from obedience to Allah, he will meet Allah (swt) on the Resurrection Day without having any proof to show for himself; and who dies while there was no pledge of allegiance on his neck, he dies a death of the days of Jahiliyyah (ignorance).” In this Hadith, the Messenger of Allah (pbuh) has made it compulsory on every Muslim to have a pledge of allegiance, i.e. Bay’ah to a Khaleefah on his neck, but he (pbuh) did not make it compulsory for every Muslim to give the pledge (Bay’ah). For the obligation is the presence of a Bay’ah on every Muslim’s neck, i.e. the existence of a Khaleefah who is entitled to a Bay’ah on the neck of every Muslim by his existence. The existence of the Khaleefah is the matter which initiates the Bay’ah on every Muslim’s neck, regardless of whether the Muslim has effectively given the Bay’ah or not. As for the unity of the Khilafah and the prohibition of having more than one Khaleefah, this is due to what Muslim narrated from Abu Sa’id Al-Khudri from the Messenger of Allah (pbuh) that he said:

"Idan an yi rantsuwar Bai'ah ga Khalifofi biyu, to a kashe na karshe daga cikinsu." Wannan a fili yake tabbatar da cewa haramun ne Musulmi su sami Khalifa fiye da daya.

“When an oath of Bay’ah has been taken for two Khulafaa’, kill the latter of them”. This clearly proves that it is forbidden for the Muslims to have more than one Khaleefah.