Is it permissible to sell an old house that was bequeathed as an endowment for the neighbors to benefit from its water tap, despite the neighbors no longer needing the tap and the scarcity of water in it? And is it permissible to sell a shop that was bequeathed to be rented out and its proceeds given as charity, knowing that it is about to collapse, and to donate its price for building a mosque?

It is permissible to sell an old building if there is fear of its collapse or if its utility has ceased, and its price should be spent on the welfare of the endowment (waqf). Consultation with the Sharia judge is advisable. If spending the money on the mosque is more beneficial, then there is no harm in it. Otherwise, it should be spent on providing water for Muslims. As for a rented house, its price should be spent on another house that can be rented, and its income should be given as charity. Ahmad (Ibn Hanbal) permitted replacing one mosque with another for a beneficial reason, and he also permitted changing the condition set by an endower if it leads to something more beneficial.