Is it permissible to sell an endowment (waqf) and donate its price for building a mosque if the endower (waqif) fears that it will be disposed of after his death, due to the absence of an institution dedicated to endowments in his country?

The fundamental principle is that an endowment (waqf) may not be sold, except in cases of necessity, such as fear of its usurpation by oppressors, or its unsuitability for the purpose for which it was endowed, or the cessation of its benefit. In these situations, it is permissible to sell it and replace it with something that serves the public interest.