It is prohibited in terms of Shari?ah to take up a job at institutions such as banks.
Although banks have other sources of income, but due to interest being predominant, there is a very strong likelihood that much of the salary is paid to the employee is sourced from Haraam avenues.
If a person is already working there then he should make a concerted effort to find another means of income. As soon as he finds an alternative means of income, he has to leave the bank. In the mean time (i.e. while looking for another source of income) the salary acquired from the bank can be used and the food bought with it can be consumed. This does not mean that if he is unemployed and he is offered a job at the bank, he can accept it. It is not permissible to accept such a job. For argument sake, even if it is established that the salary is not paid from the interest money then too it is unlawful to work in a bank (an institution of interest). This is due to the fact that the Shari?ah has prohibited any type of involvement with institutions that deal with interest. There are two main reasons for this. Firstly, Allah Ta’aala has prohibited us in the Qur?an from being an assistant of evil and vice. (Surah Maaidah: Verse no.2) By working for a bank, a person is an assistant to interest dealings that are haraam. Secondly, Rasulullah sallallahu alaihi wasallam has cursed all those that get involved in interest dealings, even if he is only recording the Interest. By working in a bank, a person is somehow involved in interest even though he is just a servant because he is making it easy for those doing the deals to complete their work. That’s why merely working for a bank is unlawful.
and Allah Ta’ala Knows Best
Mufti Ebrahim Desai