The same applies to the structure. However, the person who provided the money for it should not reclaim it as his own. This is like someone who sets aside some of his wealth to give in charity but cannot find the beggar: he should carry out his intention by giving it to another beggar rather than taking it back into his ownership, although this is not obligatory.

If a place such as this is devoted to serving the needs of another mosque, that is permissible. Indeed, even if it has become a mosque, but no one prays there, it may be transferred to another mosque where it can be put to use. Moreover, if it may be sold and its price spent on another mosque, then it is permissible to erect a structure that benefits another mosque.

He—may Allah have mercy on him—was also asked:

A man built a mosque and endowed a shop for a designated muezzin and muqīm, but none of the shop’s income was received during his lifetime. Is it permissible to receive it after his death?

He answered:

All praise belongs to Allah, Lord of all worlds.

If someone establishes an endowment but does not relinquish possession of it, the scholars hold two well-known views:

The first is that it is void. This is the position of Mālik and of Imam Ahmad according to one of the two reports from him. It is also the view of Abū Hanīfah and his companion Muhammad.