Abu Dawud Book 11, Hadith Number 2873.
Narated By Yahya b. Sa’id : ‘Abd al-Hamid b. ‘Abd Allah b. ‘Abd Allah b. ‘Umar b. al-Khattab copied for me a document about the religious endowment (waqf) made by ‘Umar al-Khattab: In the name of Allah, the Compassionate, the Merciful. This is what Allah’s servant ‘Umar has written about Thamgh. He narrated the tradition like the one transmitted by Nafi’. He added: “provided he is not storing up goods (for himself).” The surplus fruit will be devoted to the beggar and the deprived. He then went on with the tradition, saying: If the man in charge of Thamgh wishes to buy a slave for his work for its fruits (by selling them), he may do so. Mu’iqb penned it and ‘Abd Allah b. al-Arqam witnessed it: In the name of Allah, the Compassionate, the Merciful. this is what Allah’s servant ‘Umar, Commander of the Faithful, directed, in case some incident happens to him (i.e. he dies), that Thamgh, Sirmah b. al-Akwa’, the servant who is there, the hundred shares in (the land of) Khaibar, the servant who is there and the hundred shares which Muhammad (PBUH) had donated to me in the valley (nearly) will remain in the custody of Hafsah during her life, then the men of opinion from her family will be in charge of these (endowments), that these will neither be sold nor purchased, spending (its produce) where they think (necessary on the beggar, deprived and relatives). There is no harm to the one in charge (of this endowment) if he eats himself, or feeds, or buys slaves with it.