I asked Abu Al-Hasan (as), peace be upon him, and said: "May I be your ransom, I purchased a piece of land next to mine for one thousand dirhams. When I gathered the money, I was informed that the land was an endowment (waqf)." Imam (as) replied: "The purchase of endowment property is not permissible, and do not mix its yield with your wealth. Instead, give its yield to those for whom it was endowed." I said: "I do not know who its rightful beneficiaries are." Imam (as) said: "Then give its yield in charity."