What is the ruling regarding the borrower permitting a third party to use the borrowed item without explicit permission?
General Chapter
Al-Mughni
Book of Loan for Use
Primary text
Lending the item to another is prohibited because borrowing constitutes a permission (ibaha) only for the specific benefit intended, and this permission cannot be extended by the borrower to another, similar to giving away food that one was only permitted to eat. The distinction from a lease (ijarah) is that in a lease, the lessee owns the right of use in every capacity, allowing them to transfer ownership of that right, whereas the borrower only owns the right to personally actualize the benefit in the manner permitted, resembling one permitted only to eat provided food.
Supporting text
If the original owner permits this unauthorized usage, the owner may demand the equivalent rental value (ujr al-mithl) from either the original borrower or the unauthorized user. The original borrower permitted another to take the property of another without authorization, and the user utilized it without authorization. If the original borrower pays the equivalent value, they may then seek recourse against the unauthorized user because the actual realization of the benefit occurred through the user, establishing the guarantee upon them. If the unauthorized user pays the value, they cannot seek recourse against the original borrower, unless the second party was unaware of the true nature of the arrangement, in which case the guarantee might rest solely upon the original borrower because they deceived the second party by giving the item over with the pretense that its benefits could be actualized without compensation.