In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
You are not allowed to run personal business while you are at your work. Leaving what is doubtful to that which is not doubtful is required to earn halal living.
Answering your question, Dr. Wael Shehab, PhD in Islamic Studies from Al-Azhar University and currently the Imam of the Downtown Toronto Masjid in Canada,
In principle, part-time jobs and incomes are permissible, from a Shari`ah perspective, as long as the following conditions are met:
1- the work itself is permissible,
2- you are not legally committed—by your employer’s contract for example—not to work as a part-time in other companies, and
3- the law of the country doesn’t illegalize it.
As for doing some part-time assignments while you are in your full-time job, it is not allowed. You have to leave what is even doubtful to that which is not doubtful as the Prophet (peace and blessings be on him) said in a hadith.
Almighty Allah knows best.
Editor’s note: This fatwa is from Ask the Scholar’s archive and was originally published at an earlier date.