A--- Narrated Jubair Ibn Mut'im (May Allah be pleased with him): A woman came to the Prophet (Peace be upon him), he ordered her to come back to him later. She said: "What if I came and did not find you?” as if she wanted to say, "If I found you dead?" The Prophet said: "If you should not find me, go to Abu Bakr.” (Bukhari and Muslim)

'A'ishah (May Allah be pleased with her) narrated: Allah's Messenger (Peace be upon him) said to me: "Call unto me your father and brother, I want to get something written, for I fear someone to wish for it (the Caliphate), or someone else says: I deserve it (more than anyone else), but Allah and the Believers wish no one but Abu Bakr.” (Sahih Bukhari)

Abu Musa (May Allah be pleased with him) reported: When the Messenger of Allah (Peace be upon him) became ill and his illness became serious he ordered Abu Bakr to lead the people in prayer... ". "So, Abu Bakr led the prayer (during this period of illness) in the life of the Messenger of Allah (Peace be upon him).”(Bukhari and Muslim)

Besides, all companions of the Prophet (Peace be upon him) from among the Muhajirun and the Ansar paid homage to Abu Bakr and none contested thereto.