All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
The legal status of the incentive that you earned for recruiting a person to a bank depends on the legal status of the job you recruited that person for. If the bank deals with Riba (usury and interest), then the work is forbidden and the incentive you earned for recruiting that person is also forbidden because of the job being forbidden. Hence, this incentive should be spent in the general interests of the Muslims. But if you did not know that such recruiting was forbidden, then some scholars are of the view that it is permissible to gain possession that incentive and avail oneself of it. please refer to Fatwa 85917.
If, on the other hand, the bank is an Islamic bank, then there is nothing wrong with taking the incentive for recruiting people to it.
As regards keeping this job, this is permissible if it does not involve either direct engagement in something forbidden or helping in something that is forbidden, and provided that you do your job as you are required to do it.
As regards the salary being a fixed amount and a percentage from the profits, the scholars differed in opinion about it. The majority of the scholars are of the view that it is not permissible, but it was narrated from Imaam Ahmad that it is permissible, and this was also narrated from some other scholars. Ibn Qudaamah said: “If in addition to that (i.e. the percentage), he is awarded a fixed amount of money, then this is not permissible; (Ahmad) explicitly stated this, but he was also reported to have said it is permissible. However, the former is the correct opinion…. Al-Athram traced reports back to Ibn Seereen, an-Nakha‘i, Az-Zuhri, Ayyoob, and Ya‘la ibn Hakeem, that they permitted this.”
Allaah Knows best.