What is the ruling on a charitable society stipulating that only the one who pays the price of the grave may benefit from it, and that his heirs have no right to benefit from it if he is buried elsewhere?

The fundamental principle regarding conditions is permissibility and validity. Nothing is forbidden or invalidated unless the Sacred Law indicates its prohibition or invalidation. This is based on the Almighty's saying: "O you who have believed, fulfill [all] contracts," and the Prophet's (peace be upon him) saying: "Muslims are bound by their conditions."

Accordingly, if the association stipulates that only the person who paid the amount may be buried in the grave, and that if they are buried elsewhere, their heirs have no right to it, and the payer agrees to this, then the condition is valid and binding, as there is no legal evidence to invalidate it. This transaction is neither a sale nor a lease; rather, it is a permission to benefit or an ownership of the right of usufruct, which is a personal right that cannot be gifted or inherited. Thus, the owner of the usufruct benefits only themselves; they cannot rent it out, gift it, or lend it.