By Asma bint Shameem
Working in a conventional bank is not allowed because the whole system runs on interest.
And working in any department of the bank would be “assisting” in this major sin, while Allaah is telling us to cooperate in goodness and not in sin
وَتَعَاوَنُوا عَلَى الْبِرِّ وَالتَّقْوَىٰ وَلَا تَعَاوَنُوا عَلَى الْإِثْمِ وَالْعُدْوَانِ وَاتَّقُوا اللَّهَ إِنَّ اللَّهَ شَدِيدُ الْعِقَابِ
“Help you one another in Al-Birr and At-Taqwa (virtue, righteousness and piety); but do not help one another in sin and transgression.
And fear Allaah. Verily, Allaah is Severe in punishment.”
(Surah al-Ma’edah:2)
And Allaah says:
مَّن يَشْفَعْ شَفَاعَةً حَسَنَةً يَكُن لَّهُ نَصِيبٌ مِّنْهَا وَمَن يَشْفَعْ شَفَاعَةً سَيِّئَةً يَكُن لَّهُ كِفْلٌ مِّنْهَا وَكَانَ اللَّهُ عَلَىٰ كُلِّ شَيْءٍ مُّقِيتًا
“Whosoever intercedes for a good cause will have the reward thereof, and whosoever intercedes for an evil cause will have a share in its burden. And Allah is Ever All-Able to do (and also an All-Witness to) everything.“
(Surah an-Nisaa:85)
Jaabir radhi Allaahu anhu said:
“The Messenger of Allaah Sal Allaahu Alaiyhi wa Sallam CURSED ten people: the one who consumes ribaa, the one who pays ribaa, the one who writes it down, the two who witness it, the one who makes it lawful, the one for whom it is made lawful...” (Saheeh Muslim)
The scholars of the Standing Committee said:
“It is not permissible for a Muslim to work as a guard for banks that deal with riba, because this is a kind of cooperating in sin and transgression, and Allaah has forbidden that. Most of the banks deal with riba, so you have to look for a halaal means of earning a living, not this way.”
(Fataawa Islamiyyah, 2/401, 402)
And Allaah knows best