What is the ruling on usury if it is as follows: The bank buys a commodity for 8,0, then the customer sells it to another merchant in coordination with the bank and for a commission to the merchant, then the customer pays the bank 10,0 in installments, for the purpose of buying a house that contains a mosque?

If the bank owns the iron and sells it to you in installments, and then you give it to a merchant to sell it for you in exchange for a commission, and the merchant sells it to a third party who has no connection with the bank, then there is no objection to that.

However, if the merchant sells it to the original supplier from whom the bank bought the iron, or to a partner of the bank, then this is a circumvention of usury (the triple or triangular stratagem), and it is forbidden. This is because the commodity will return to its original owner, and the transaction will be money for money.

For the transaction to be valid, it is stipulated that the bank's ownership of the iron and your ownership of it must be real and not merely nominal.

This transaction combines Murabaha (the bank buying the iron and selling it to you at a profit) and Tawarruq (your buying the iron on credit to sell it for cash). Murabaha and Tawarruq are permissible under Sharia conditions, and this transaction is not considered a loan but rather a sale and purchase.