On arriving at Medina...
On arriving at Medina, the Prophet had created fraternal relationships, making a muhajir brother of an ansari; and every ansari shared all his property half and half with his muhajir brother; so much so that if an ansari's inheritance was divided among his brothers and sisters, the muhajir "brother" was included in it.
Abu Bakr was made brother of Kharijah bin Zayd; 'Umar and 'Utban bin Malik Ansari were made brothers, as were 'Uthman and Aws bin Thabit Ansari; and so on.[^4] Only 'Ali was left out of this fraternity, the Prophet declaring that 'Ali was the brother of the Prophet himself.[^5] On acquiring the property of Banu Nazir, the Prophet on his own decided to divide it among the muhajirin and release Ansar from this burden.
He did so, and included two extremely poor Ansar in the list - Abu Dajjanah and Sahl ibn Haneef.[^6] So all mahajirin, including Abu Bakar, 'Umar and 'Uthman, got their shares from that land and it became their personal property. It was not for their "maintenance" only. In the same way Fadak became a personal property of the Prophet; and he managed it himself.[^7] Then another 'Aya came:- "Andgive to the near of kin his due ..." (Qur'an, 17:26).
The Prophet asked Jibril the meaning of this revelation. He said: Give Fadak to Fatimah; it will be a source of income to her and her children.[^8] The Prophet gave Fadak to Fatimah; and she was using it as her own property; her agent was there to look after her interests. This continued till the Prophet died and Abu Bakr took the possession of Fadak by force. Now Fatimah protested against this usurpation of her property, saying that the Prophet had given it to her.
Abu Bakr asked her to produce witnesses to prove it. Now Fatimah was already in possession of the property; and according to the Islamic principles, possession itself is a sufficient proof of ownership. If Abu Bakr claimed that property for himself or for Muslim nation, then it was he, as claimant, who should have produced witnesses to support his claim. But he put the onus of proof on Fatimah, disregarding Islamic Law. Again, as he was a claimant, he should not have judged the case himself.
But he did not care for judicial niceties so long as his purpose was served. Anyhow, Fatimah brought 'Ali and Umm Ayman (widow of Zaid b. Haritha).