Because ‘Umar (may Allah be pleased with him) endowed (his land in Khaybar) and said that if its administrator also eats from it, there is no harm. Here, he did not specify whether he himself would be its administrator or someone else. The Prophet (peace and blessings be upon him) said to Abu Talha (may Allah be pleased with him) that I think if you wish to give your land (the garden of Bairuha’) in charity, then give it to your relatives. He replied that he would do so. Thus, he distributed it among his relatives and the sons of his uncle.

When Abu Talha (may Allah be pleased with him) said that among my wealth, the garden of Bairuha is the most beloved to me, and I give it in charity in the way of Allah, the Prophet (peace and blessings of Allah be upon him) approved it (even though he did not specify to whom he would give it). But some people (the Shafi'is) said that unless it is specified for what purpose the charity is given, it will not be valid, and the first opinion is more correct.

Narrated Ibn `Abbas: The mother of Sa`d bin 'Ubada died in his absence. He said, "O Allah's Apostle! My mother died in my absence; will it be of any benefit for her if I give Sadaqa on her behalf?" The Prophet said, "Yes," Sa`d said, "I make you a witness that I gave my garden called Al Makhraf in charity on her behalf."