Is it permissible to make a sign for a bank, knowing that this might be considered aiding in usury?

It is not permissible to work in what was mentioned, whether in a usurious bank or other establishments founded upon forbidden practices, such as selling alcoholic beverages. This is because doing so constitutes cooperation in sin, and one who assists in sin is a partner in it, based on the Almighty’s saying: "So never will I be a supporter of the criminals," and His saying: "And do not cooperate in sin and aggression."