When during the lifetime of the Holy Prophet, the Muslims conquered Khyber, the Holy Prophet deputed Mahisa bin Masud Ansari to Fidak a neighhouring township to invite the inhabitants to Islam. The township was a Jewish settlement, the chief being a Jew Yusha bin Nun. After the fall of Khyber, the Jews of Fidak were in no mood to offer resistance. The Jews submitted, and offered to surrender one half of their land.
About the disposal of the land in Fidak, God revealed:
"What Allah has made this people (the Jews) to deliver,
To conquer which you did not lead any force,
Vests in the Apostle,
And Allah empowers His Apostles over whom He pleases."
The Holy Prophet accordingly reserved the land for himself. The proceeds from the property were utilised by the Holy Prophet for the maintenance of His family. These were also utilised for charity, and for the relief of those in distress.
After the death of the Holy Prophet Fatima as the successor of the Holy Prophet claimed the land at Fidak. Abu Bakr did not concede the claim. Abu Bakr declared that He had heard from the Holy Prophet that prophets leave no inheritable property and that all that they have is public trust.
Fatima died during the caliphate of Abu Bakr. After the death of Abu Bakr, Ali and Abbas lodged before Umar a claim to the land of Fidak. Umar upheld the decision of Abu Bakr. He held that the land was a reserve of the Holy Prophet, but it was a reserve for public purposes, and after his death the reserved vested in the State, and could not be claimed by his successors as if it was his personal property.
On this occasion, explaining his decision, Umar said:
"The Holy Prophet used to take from the land of Fidak the maintenance of his family for the year. The rest he spent in the way of Allah. This was the Holy Prophet's practice as long as he lived. When the Holy Prophet, on whom be peace and blessings, died, Abu Bakr said 'I am the successor of the Apostle of Allah'. So he took possession of land and used it as the Holy Prophet had used it. Then Abu Bakr died. Now I am the successor of Abu Bakr, and I have had the land in my possession for two years, and have done with it as the Holy Prophet, and Abu Bakr had done before."
The upshot of Umar's decision was that the land at Fidak was a public trust to which the ordinary law of inheritance did not apply.