What is the ruling on a partner selling to the shop a pump that the partner had previously purchased at the same price as the shop's purchase, knowing that the shop was aware of the first sale but unaware of the second?

The aforementioned sales transaction is permissible because it fulfills the pillars of sale and its conditions for validity. There is no objection to selling at three times the price as long as it is free from deception or treachery. It is stipulated that the seller should not be an agent for the shop in purchasing for himself, because an agent is not allowed to favor himself. Some scholars have prohibited an agent from selling to or buying for himself, even at the market price, for fear of favoritism.