What is the Islamic legal ruling concerning the damage of a car given to someone for rent, as a courtesy, or for long-term lease, and what compensation is due to the owner?

There are two scenarios for handing over a car to a colleague: either it is a rental (ijarah), in which case the renter is only liable for damage caused by transgression or negligence. Or it is a loan (i'arah): if the car is damaged due to the borrower's transgression or negligence, he is liable. If it is damaged without such, there is a difference of opinion regarding his liability, and some scholars, such as the Shafi'is and Hanbalis, do not consider him liable if the damage occurred during authorized use. So, if the borrower's transgression, such as speeding, is proven, he is obligated to guarantee the damage; otherwise, there is no liability upon him. If the lender and borrower differ, the borrower's statement is accepted with his oath in the absence of evidence.