Endowment (Al-Waqf)
It is one of the best means of proximity to Allah. The pious ancestors, may Allah grant them mercy, dedicated the best of their wealth for the means of proximity to Allah—especially in building and maintaining the mosques. As Prophet Muhammad, peace and blessings be upon him and his progeny, said: ((Whoever builds a mosque, even if it was as small as the nest of a small passerine birds, then Allah will build him/her a house in Paradise)).
No one may make any commercial deals using the original money dedicated to the endowment and its branches. It is the property of Allah, the Exalted. Consequently, it can be neither sold, transferred, nor commercially exchanged. Whoever is in charge of the endowment must spend its profits and revenues for its legal ways that was determined by the endower.
S/he should choose and do the best, so he must not sell the crops with the same price, after knowing that the price has been raised because of the increasing of the demands. For example, the stores are not to be rented with the same price after knowing that the price has been raised because of the increasing of the demands. Therefore, what the people do, like selling by hand and the renting the endowments without investigating about the new prices, is invalid and forbidden, and it is a clear violation.