Islam is a religion of morality and goodness. It aims at building a solid society on bases of purity, modesty, morals, and good manners. By the same token, Islam blocks all ways that lead to evil to the extent that Muslim jurists adopt a juristic principle that reads: What is conductive to the Haram (unlawful) is itself Haram.
Sheikh Ahmad Kutty, a senior lecturer and an Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states that: “As a Muslim, you are not allowed to work in a restaurant that serves alcohol or foods that are considered Haram. In Islam it is not only considered Haram to consume what is Haram but the prohibition also extends to promoting or condoning or aiding or assisting in the commission of the act. By working in such a restaurant, you are undoubtedly contributing to such things. Therefore, it is not considered lawful for a Muslim to continue in such a job.
You would undoubtedly be concerned about losing livelihood. Allah has promised us in the Qur’an that He would certainly provide for us should we remain conscious of Him and strive earnestly to obtain a Halal source of income. You are, therefore, best advised to exercise your imagination to find Halal options; when Allah forbids something in Islam, He has made sure to provide us with substitutes that are Halal. Allah says in the Qur’an, “And whosoever keepeth his duty to Allah, He maketh his course easy for him.” (At-Talaq: 4).
It is also worth mentioning that there is virtually no blessing in earnings that are purely Haram. A penny of Halal is better than a million dollars earned through Haram. One of the conditions for acceptance of Prayer in Islam is to earn a living through purely Halal sources.
Therefore, you are best advised to seek to find a source of livelihood that is purely Halal; if you have the will and sincere intention and strive for it, Allah will surely help.”