Sahih Muslim 2387
Sahih Muslim · Book 44: The Book of the Merits of the Companions · The Virtues Of Abu Bakr As-Siddiq (RA)
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:
حَدَّثَنَا عُبَيْدُ اللَّهِ بْنُ سَعِيدٍ ، حَدَّثَنَا يَزِيدُ بْنُ هَارُونَ ، أَخْبَرَنَا إِبْرَاهِيمُ بْنُ سَعْدٍ ، حَدَّثَنَا صَالِحُ بْنُ كَيْسَانَ ، عَنِ الزُّهْرِيِّ ، عَنْ عُرْوَةَ ، عَنْ عَائِشَةَ ، قَالَتْ قَالَ لِي رَسُولُ اللَّهِ صلى الله عليه وسلم فِي مَرَضِهِ " ادْعِي لِي أَبَا بَكْرٍ وَأَخَاكِ حَتَّى أَكْتُبَ كِتَابًا فَإِنِّي أَخَافُ أَنْ يَتَمَنَّى مُتَمَنٍّ وَيَقُولَ قَائِلٌ أَنَا أَوْلَى . وَيَأْبَى اللَّهُ وَالْمُؤْمِنُونَ إِلاَّ أَبَا بَكْرٍ " .
I have better claim to it, whereas Allah and the Faithful do not substantiate the claim of anyone but that of Abu Bakr.