What is the ruling on exchanging a money debt for rice, if the price of a sack of rice is equivalent to a specific amount of money agreed upon at the time of repayment, and this is instead of repaying the debt in cash?

If the two parties agree that the owner of the capital gives four thousand in exchange for bags of rice to be delivered at specific times, this transaction is valid and is called "Salam" (forward sale) with conditions. These conditions include: paying the price in full and in advance at the contracting session, specifying the quantity of rice and its characteristics that affect the price, and specifying the delivery date. The proof for these conditions is the Hadith (definition) of Ibn Abbas (may Allah be pleased with both of them): "(Whoever pays in advance for something, let it be for a known measure, and a known weight, to a known term)."

However, if the transaction is a loan, meaning the merchant borrows money and repays it in cash, then offers to repay the debt with rice equivalent to the amount due on the day of repayment, this scenario is permissible, provided there is no prior condition for this, or a prevailing custom in the country, and that the exchange is at the price of rice on the day of repayment.