What is the ruling on taking an amount of 200,0 Riyals in exchange for mediating the sale of a shop, knowing that the seller wanted 1,400,0 Riyals, and the buyer agreed to 1,600,0 Riyals, and that the sale took place without the two parties seeing each other?

The action of the questioner—increasing the price of the shop beyond what the seller specified and taking the difference without the seller's permission—is considered deception, unlawful acquisition of wealth, and is forbidden in Islamic law. He must repent to Allah and return the excess amount to the seller unless the seller waives it. The permissible alternative, according to Islamic law, is to agree upon a specific commission with either the seller or the buyer, or to agree with the seller on a certain price, and anything in excess of that price would belong to the questioner, as has been authentically reported from Ibn Abbas and Al-Zuhri.