To what extent is it permissible to purchase goods in installments from a bank at their original price agreed upon with the seller, knowing that the bank will take a commission from the seller?

Case One: The bank stipulates that the borrower must purchase the commodity from a specific store from which the bank receives a commission. This is forbidden because it is a loan that brings a benefit to the lender, and every loan that brings a benefit is usury (riba). Furthermore, this condition contradicts the essence of a loan contract, which allows the borrower to dispose of the money as they wish.

Case Two: The bank does not stipulate this. This case is permissible, though it is unlikely.