A'isha reported that Allah's Messenger (ﷺ) in his (last) illness asked me to call Abu Bakr, her father, and her brother too, so that he might write a document, for he feared that someone else might be desirous (of succeeding him) and that some claimant may say: I have better claim to it, whereas Allah and the Faithful do not substantiate the claim of anyone but that of Abu Bakr.
Explanation & Benefits
Shaykh Maulana Abdul Aziz Alvi
Hadith Commentary: Benefits and Issues: From this hadith, it is explicitly established that the Prophet (sallallahu alayhi wa sallam) intended to appoint Abu Bakr (radi Allahu anhu) as the caliph. However, due to this prophecy that neither Allah nor the believers would approve of anyone’s caliphate except Abu Bakr (radi Allahu anhu), the Prophet (sallallahu alayhi wa sallam) postponed his intention.
Source: Tuhfat al-Muslim: Commentary on Sahih Muslim, Page: 6181