Sahih al-Bukhari 3711, 3712
Narrated 'Aisha:
Fatima sent somebody to Abu Bakr asking him to give her her 
     inheritance from the Prophet (ﷺ) from what Allah had given to His Apostle 
     through Fai (i.e. booty gained without fighting). She asked for the 
     Sadaqa (i.e. wealth assigned for charitable purposes) of the Prophet (ﷺ) 
     at Medina, and Fadak, and what remained of the Khumus (i.e., 
     one-fifth) of the Khaibar booty. Abu Bakr said, "Allah's Messenger (ﷺ) said,
     'We (Prophets), our property is not inherited, and whatever we leave 
     is Sadaqa, but Muhammad's Family can eat from this property, i.e. 
     Allah's property, but they have no right to take more than the food 
     they need.' By Allah! I will not bring any change in dealing with the 
     Sadaqa of the Prophet (and will keep them) as they used to be observed
     in his (i.e. the Prophet's) life-time, and I will dispose with it as 
     Allah's Messenger (ﷺ) used to do," Then 'Ali said, "I testify that None has 
     the right to be worshipped but Allah, and that Muhammad is His 
     Apostle," and added, "O Abu Bakr! We acknowledge your superiority." 
     Then he (i.e. 'Ali) mentioned their own relationship to Allah's 
     Apostle and their right. Abu Bakr then spoke saying, "By Allah in 
     Whose Hands my life is. I love to do good to the relatives of Allah's 
     Apostle rather than to my own relatives"
حَدَّثَنَا أَبُو الْيَمَانِ، أَخْبَرَنَا شُعَيْبٌ، عَنِ الزُّهْرِيِّ، قَالَ حَدَّثَنِي عُرْوَةُ بْنُ الزُّبَيْرِ، عَنْ عَائِشَةَ، أَنَّ فَاطِمَةَ ـ عَلَيْهَا السَّلاَمُ ـ أَرْسَلَتْ إِلَى أَبِي بَكْرٍ تَسْأَلُهُ مِيرَاثَهَا مِنَ النَّبِيِّ صلى الله عليه وسلم فِيمَا أَفَاءَ اللَّهُ عَلَى رَسُولِهِ صلى الله عليه وسلم، تَطْلُبُ صَدَقَةَ النَّبِيِّ صلى الله عليه وسلم الَّتِي بِالْمَدِينَةِ وَفَدَكٍ وَمَا بَقِيَ مِنْ خُمُسِ خَيْبَرَ‏.‏ فَقَالَ أَبُو بَكْرٍ إِنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏
"‏ لاَ نُورَثُ، مَا تَرَكْنَا فَهْوَ صَدَقَةٌ، إِنَّمَا يَأْكُلُ آلُ مُحَمَّدٍ مِنْ هَذَا الْمَالِ ـ يَعْنِي مَالَ اللَّهِ ـ لَيْسَ لَهُمْ أَنْ يَزِيدُوا عَلَى الْمَأْكَلِ ‏"‏‏.‏ وَإِنِّي وَاللَّهِ لاَ أُغَيِّرُ شَيْئًا مِنْ صَدَقَاتِ النَّبِيِّ صلى الله عليه وسلم الَّتِي كَانَتْ عَلَيْهَا فِي عَهْدِ النَّبِيِّ صلى الله عليه وسلم، وَلأَعْمَلَنَّ فِيهَا بِمَا عَمِلَ فِيهَا رَسُولُ اللَّهِ صلى الله عليه وسلم‏.‏ فَتَشَهَّدَ عَلِيٌّ، ثُمَّ قَالَ إِنَّا قَدْ عَرَفْنَا يَا أَبَا بَكْرٍ فَضِيلَتَكَ‏.‏ وَذَكَرَ قَرَابَتَهُمْ مِنْ رَسُولِ اللَّهِ صلى الله عليه وسلم وَحَقَّهُمْ‏.‏ فَتَكَلَّمَ أَبُو بَكْرٍ فَقَالَ وَالَّذِي نَفْسِي بِيَدِهِ، لَقَرَابَةُ رَسُولِ اللَّهِ صلى الله عليه وسلم أَحَبُّ إِلَىَّ أَنْ أَصِلَ مِنْ قَرَابَتِي‏.‏