If I lend someone money through my credit card (I buy him an item) and he pays me back for the price of the item. But my credit card rewards gives me cash back. Is that ribbis?
Answer:
This does not involve a problem of ribbis. The problem of ribbis arises when the borrower gives the lender something extra in exchange for the loan (and possibly when a third party does so).
In this case, the cash back reward is not in any way related to the loan, and therefore there is no concern of ribbis.
Note that there is room to debate the entiere nature of a loan by credit card payment (the company, and not the owner, actually lays out the money).
If, for some reason, your account was never debited, it follows that there is no loan between you and the borrower, and he will not owe you the money at all. If, however, the money was rewarded back for some reason, this is not a reason for the loan to be cancelled, and the borrower must pay the debt.
