What is the ruling on buying a car from another person, where the car has installments due to a usurious bank, knowing that the buyer is the one who asked the seller to purchase it because he is a client of the bank, on condition that the buyer pays the installments directly to the seller without dealing with the bank?

It is permissible to buy the car from its owner and pay its price in installments to him. The fact that the car was bought with an interest-based loan does not affect this, because the prohibition of usury is related to thew borrower's responsibility, not to the car itself. However, the buyer sins if he enticed the seller into an usurious transaction and requested it from him, due to the Almighty's saying: "And cooperate in righteousness and piety, but do not cooperate in sin and aggression." What was obligatory was to forbid him and denounce his action. Therefore, one must seek forgiveness for what was done.