One of my close acquaintances asked me to look for a piece of land for him to buy. When I found the land I said to him, “It is offered for sale – for example – for 10 riyals, in addition to one riyal as a commission for the people who helped me conclude the transaction.” The man agreed and the transaction was concluded. After a short period of time, the buyer died, may Allaah have mercy upon his soul.
My question is: What is the ruling in case that I alone took that one riyal of commission?
If it is impermissible for me to take this amount of money, should I pay it back to the heirs or give it in charity? Am I considered dishonest because that man did not know that it was me who took the commission? It should be known that he bought that land to help me and two other people, and the total buying price did not exceed the due market price for this piece of land.

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, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

It seems that the buyer in question deputized you to buy a piece of land without making any specifications. This is a general agency that necessitates working for the benefit of the principal. In other words, you should buy the best piece of land in return for the least price. However, you contradicted the requirement of that agency since you added a commission which denotes working for your own benefit. Hence, your goal contradicted with the goal of the principal, thus, you are questioned for this act.

Buying the land at market price does not discharge you because doing so most probably involves accusation. Such an accusation can not be dismissed by a case that does not result in an accusation. Moreover, you are also questioned for this act because of another reason: that you pursued commission may drive you to hasten in buying an inappropriate piece of land or the like.

Accordingly, you should pay the money taken as a commission to the heirs, whether you let them know about this incident or not. It is impermissible for you to give this money in charity on behalf of the deceased as long as you can pay the money to the heirs. You should seek the forgiveness of Allaah for lying to your principal. May Allaah Guide you to do whatever pleases Him.

Allaah Knows best.