The Book Pertaining to the Merits of the Companions (Allah Be Pleased With Them) of the Holy Prophet (May Peace Be Upon Him) (Kitab Al-Fada'il Al-Sahabah)

Muslim :: Book 31 : Hadith 5879

A'isha reported that Allah's Messenger (may peace be upon him) 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.