What is the ruling on an employee selling his car mortgaged to the bank if the buyer pays its price in full or in installments, and the employee undertakes to pay the remaining installments to the bank without the bank's knowledge? And if the sale is forbidden, how can it be made permissible? And what are the consequences for the buyer in this situation?

Selling a mortgaged item without immediate payment of the mortgagee's right is a matter of scholarly disagreement: some consider it void, while others deem it valid but contingent upon the mortgagee's approval. According to the second opinion, it is permissible to purchase a mortgaged car, and the sale becomes effective after the mortgage is settled, provided that the price and the term (if any) are known.