What is the ruling on working for a company that installs and repairs alarm systems, most of whose clients are usurious banks?

The basic ruling is that it is permissible to work for a company specialized in installing and repairing alarm systems, unless it necessitates installing them for an institution whose activity is forbidden. In such a case, it is prohibited due to the assistance it provides in sin, in accordance with the Almighty's saying: "And cooperate in righteousness and piety, but do not cooperate in sin and aggression." Accordingly, there is no harm in working for the institution in question, provided the worker does not directly install them for an institution based on usury or forbidden activities.