Ruling on unlawful money gained before one's repentance
23-11-2016 | IslamWeb
Question:
Assalaamu alaykum wa rahmatullaahi wa barakaatuhu. Dear respecter Brother, I have a question regarding my friend. He used to work in the UAE the last couple of years but has now come back to his home country. While he was explaining how his work and salary and so on were over there, he mentioned that there was some opportunity to earn more money. I asked him what it was, and he explained that while he was working for a petrol station, the supervisor and some other staff members would steal petrol and sell it on the black market. My friend also earned money that way and very soon made a million. Praise be to Allaah, he has completely changed and does good deeds such as the prayer and all other deeds. He also asks forgiveness from Allaah for what he has done during those days. Now my question is: praise be to Allaah, he repended to Allaah, and Allaah will surely forgive him for all the money he earned. With his savings, he bought some property as well as a house. The last time I met him, we went to a restaurant and had some food, and he paid for it. At the time, I thought that it would be halal for me given that he repended and has become a very good Muslim. Now I do not know how to advise to him because I do not know how to deal with him. Please advise me regarding my question: has the money become halal for him now that he has repented?
Answer:
All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad 
is His slave and Messenger.
Indeed, your friend did well as he repented to Allah. He should know that the conditions of repentance are as follows: (a) to stop committing the sin, (b) to feel remorse for having done it, and (c) to be resolved not to return to it in the future. If there are rights that he owes to someone else, then he must return the right to him, and he is not acquitted from sin just by fulfilling the three conditions mentioned above.
You are wrong in saying that “Allah will surely forgive him for all the money he earned,” as it is not permissible to assert this, but if he sincerely repents and fulfills all those conditions, then we hope that Allah will forgive him.
Therefore, he must try to give back the stolen money to its owners. If we presume that he is unable to reach them and he has despaired from finding them, then he must give that money in charity and intend the reward for them.
Ibn al-Qayyim 
said in Zaad Al-Ma’aad, “If someone receives money regarding which he has no right to own it Islamically and he wanted to get rid of it, then if it is not possible to give it to its owner, he may pay the debt of the owner, and if this is also not possible, then he must give back the money to his heirs. If this is not possible, then he may give it in charity and intend the reward for him.”
If he is unable to know the amount of this forbidden money, then he should try to estimate it to such an extent that he thinks that he has acquitted himself from sin.
As for eating food which he had paid for, then this is not forbidden for you. In general, dealing with someone whose money is mixed is not forbidden. As-Suyooti when talking about the rule "If the lawful and unlawful are mixed, then the unlawful prevails", said, “As for dealing with someone of whom most of the money is unlawful and he does not know exactly which money is unlawful in particular, it is not forbidden according to the most correct opinion (of scholars), but it is disliked.”
Allah knows best.