سنن النسائي

It was narrated that Yazid -Ibn Ruzaiq- said: "Ibn 'Awn narrated to us, from Nafi', from Ibn 'Umar, from 'Umar, who said: 'I acquired some land at Khaibar. He came to the Prophet (ﷺ) and said: I have acquired some land at Khaibar, and I have never been given any wealth that is more precious to me than it. What do you command me to do with it? He said: If you wish, you can 'freeze' it and give it in charity. So he gave it in charity on condition that it would not be sold, given away or inherited, to the poor, relatives, slaves, for the cause of Allah, guests and wayfarers. There is no sin on the one who administers it if he eats from it on a reasonable basis and feeds his friend, with no intention of becoming wealthy from it.'"