Did the Prophet appoint ‘Ali as khaleefah?
Question

                What is the ruling on people who claim that the Messenger (peace and blessings of Allaah be upon him) appointed ‘Ali (may Allaah be pleased with him) as khaleefah, and say that the Sahaabah (may Allaah be pleased with them) conspired against him?
Praise be to Allah.
    This opinion is not known among any of the Muslim groups 
    apart from the Shi’ah, and it is a false view which has no basis in the 
    ahaadeeth that have been proven from the Messenger of Allaah  (peace and 
    blessings of Allaah be upon him). On the contrary, a great deal of evidence 
    shows that the khaleefah after the Prophet  (peace and blessings of 
    Allaah be upon him) was Abu Bakr al-Siddeeq (may Allaah be pleased with him 
    and with all the companions of the Prophet  (peace and blessings of 
    Allaah be upon him)). But the Prophet  (peace and blessings of Allaah be 
    upon him) did not state that clearly and he did not appoint him in any 
    definitive sense; rather he gave commands which indicated that, when he told 
    him to lead the people in prayer when he (the Prophet  (peace and 
    blessings of Allaah be upon him)) was sick, and when he told him about the 
    leadership of the Muslim community after his death, saying, “Allaah and the 
    believers will only accept Abu Bakr.” Hence the Sahaabah (may Allaah be 
    pleased with them) gave their allegiance (bay’ah) to Abu Bakr and they were 
    unanimously agreed that Abu Bakr was the best among them. It was reported in 
    the hadeeth of Ibn ‘Umar (may Allaah be pleased with him) that the Sahaabah 
    (may Allaah be pleased with them) used to say during the Prophet’s life: 
    “The best of this ummah after its Prophet is Abu Bakr, then ‘Umar, then 
    ‘Uthmaan,” and the Prophet  (peace and blessings of Allaah be upon him) 
    approved of their saying that. Mutawaatir reports from ‘Ali (may Allaah be 
    pleased with him) show that he used to say, “The best of this ummah after 
    its Prophet is Abu Bakr then ‘Umar.” And he (may Allaah be pleased with him) 
    used to say, “No one is brought to me who prefers me over them, but I will 
    whip him with the hadd punishment for telling lies.” He never claimed that 
    he was the best of this ummah, or that the Messenger of Allaah  (peace 
    and blessings of Allaah be upon him) had appointed him as khaleefah. He 
    never said that the Sahaabah (may Allaah be pleased with them) had wronged 
    him and taken away his rights. When Faatimah (may Allaah be pleased with 
    her) died he gave a second pledge of allegiance (bay’ah) to Abu Bakr, as 
    confirmation of his first pledge and to demonstrate to the people that he 
    was with the jamaa’ah (the main group of Muslims) and that he had no 
    reservations in his heart against giving his allegiance to Abu Bakr (may 
    Allaah be pleased with them all). When ‘Umar was stabbed, he appointed six 
    of those whom the Prophet  (peace and blessings of Allaah be upon him) 
    had testified were guaranteed Paradise, for them to appoint one of their 
    number as ‘Umar’s successor; among these six was ‘Ali, who never denounced 
    ‘Umar, either whilst he was still alive or after his death. ‘Ali did not say 
    that he was more entitled than any of them to be khaleefah, so how can 
    anyone have the right to tell lies about the Messenger of Allaah  (peace 
    and blessings of Allaah be upon him) and say that he appointed ‘Ali as 
    khaleefah? ‘Ali himself never made any such claim, and none of the Sahaabah 
    claimed that for him. Rather they were unanimously agreed that the caliphate 
    of Abu Bakr, ‘Umar and ‘Uthmaan was valid; ‘Ali acknowledged that and he 
    cooperated with all of them in jihad, shoora (consultation), etc. Moreover, 
    the Muslims after the Sahaabah were agreed upon that which the Sahaabah had 
    been agreed on. After all this, it is not permissible for anyone or for any 
    group, Shi’ah or others, to claim that ‘Ali was the appointed successor, or 
    that the caliphate before him was false. Similarly, no one has the right to 
    say that the Sahaabah wronged ‘Ali and took away his rights. Rather this is 
    the falsest of falsehoods, and it is thinking badly of the Companions of the 
    Messenger of Allaah  (peace and blessings of Allaah be upon him), 
    including ‘Ali (may Allaah be pleased with him and with them all). 

    Allaah has protected the ummah of Muhammad  (peace and 
    blessings of Allaah be upon him) and kept it from agreeing on misguidance. 
    It was narrated in a saheeh report in many ahaadeeth that the Prophet  
    (peace and blessings of Allaah be upon him) said: “A group of my ummah will 
    continue to adhere to the truth and to prevail.” It is impossible that the 
    noblest generation of this ummah could agree on falsehood, supposedly the 
    caliphate of Abu Bakr, ‘Umar and ‘Uthmaan. No one says this who believes in 
    Allaah and the Last Day, and no one says this who has the slightest insight 
    into the rulings of Islam.