What is the ruling on working in banks as a lawyer and defending their rights?

The profession of law is permissible, provided that justice is observed and lying is avoided. Therefore, a lawyer must defend their client if the client is in the right, and advise them to drop the case if they are in the wrong. Working with Islamic banks is permissible, but usurious banks are not permissible to work with, nor is it permissible to cooperate in defending their debts, due to the Almighty's saying: "And cooperate in righteousness and piety, but do not cooperate in sin and aggression."