I have been offered a job in a bank that has both Islamic and commercial branches, and the interview was for a job in a commercial bank, but when I hinted to them that I wanted to work in the Islamic branch, I was told that they are in the process of turning the entire bank into an Islamic bank. One of the people there was an expert in Islamic banking, and he said that he was there to seek two rewards: the reward for turning the bank into an Islamic one and the reward for working in an Islamic bank.

My question has to do with the period prior to the change: is it permissible for me to work in a commercial bank until it becomes an Islamic bank? Is my work regarded as rewardable, because I am playing a role in the foundation of an Islamic bank, and that is based on my experience in Islamic banking, and also my administrative post. Please note that I am currently working in an Islamic bank, but I am not happy because there are serious and unIslamic practices in it that overstep the mark.

Praise
be to Allah.

Firstly: 

it
is not permissible to work in commercial banks which do not pay attention to
the rulings of Islamic sharee‘ah in their transactions or in some of them,
because that comes under the heading of haraam work and of cooperating in
sin and transgression, as those banks base many of their transactions on
riba (usury), gambling and other kinds of transactions that are contrary to
sharee‘ah. 

Please see the answer to questions no. 90131,
104930 and 153084

Secondly: 

If
the Islamic bank is really operating in accordance with the rulings of
Islamic sharee‘ah, then it is permissible to deal with it and work in the
bank. 

But if these banks are Islamic in name only, and they deal with riba and
other haraam transactions, then dealing with them is haraam even if they
call themselves Islamic banks, because what matters is actual facts, not
mere appearances, and what matters is the reality of things, not what they
are called. 

Please see the answer to question no. 47651.

Thirdly: 

if
the bank has Islamic branches that pay attention to shar‘i rulings in their
operations, and other branches that do not pay attention to shar‘i rulings,
it is permissible to work in the Islamic branches but not in others, if they
really do adhere to Islamic rulings and they have their own system that is
not subject to the general system of the riba-based bank, and it is
supervised by a trustworthy sharee‘ah board. 

Please see the answers to questions no. 106602 and
118294

Fourthly: 

With regard to working in banks that have started to Islamise, if these
banks are in the process of actually changing and getting rid of their
former riba-based accounts and transactions, and moving towards Islamisation
in a serious manner, and correcting their procedures, and the work does not
involve starting or renewing haraam dealings, then there is nothing wrong
with working for it and being paid for that work, if it is done with a good
intention and sincerely for the sake of Allah, on condition that the bank
should have a trustworthy sharee‘ah board to supervise the Islamisation
process. That board should also supervise the bank’s operations in the
future, and the administration of the bank should adhere to the decisions of
the trustworthy board. 

But if the actual transformation process is slow and is not serious, and the
bank is still involved with new riba-based dealings, and it is waiting for
the right time, or the right circumstances, or the right time to repent…
Then it is not permissible to work in this bank, because the haraam dealings
are still going on, with no excuse. In order to attain forgiveness of what
has passed, Allah, may He be exalted, has stipulated that the accountable
person should refrain from committing new acts of disobedience as He, may He
be exalted, says (interpretation of the meaning): “Say
to those who have disbelieved, if they cease (from disbelief) their past
will be forgiven. But if they return (thereto), then the examples of those
(punished) before them have already preceded (as a warning)”
[al-Anfaal 8:38]. 

Shaykh ‘Abd al-‘Azeez al-Fawzaan (may Allah preserve him) said: 

It
is permissible to work in Islamic banks so long as they adhere to the
guidelines set out by the sharee‘ah committees and boards. It is also
permissible to work in banks that have started to change over to be Islamic
banks. 

As
for working in riba-based banks, it is not permissible, even if the work is
in a permissible field. End quote.

http://fuqaha.islammessage.com/archive/index.php?t-510.html&s=53ce64adaf1d90f0af9a9b203875407f 

And Allah knows best.