Is it permissible to deposit money in banks and to take out car loans?

The basic ruling on depositing money in banks and dealing with them in car loans and the like is to differentiate between Islamic banks, which adhere to Sharia (definition) principles in their financial transactions, and conventional banks. It is permissible to deal with Islamic banks and deposit money with them for safekeeping or investment, as well as to engage with them for murabaha to purchase a car or to finance projects through one of the Islamic financing formulas.

As for usurious (conventional) banks, it is not permissible to deal with them, even by merely depositing money, because doing so constitutes cooperation in sin. Allah Almighty says: "And cooperate in righteousness and piety, but do not cooperate in sin and aggression. And fear Allah; indeed, Allah is severe in penalty." [Al-Ma'idah: 2]. It is even more prohibited to borrow from them with interest, or to buy a car, build a house, or anything else, as all of this is forbidden and should not be undertaken unless there is a dire necessity that permits committing the forbidden.