Is it permissible in a currency exchange (sarf) contract to leave the received amount as a trust (amanah) with the other party to be delivered later to my brother, the agent, knowing that the basic principle is immediate mutual possession (al-muqabadah) at the time of the contract?

Scholars have differed on the validity of an agent being both the receiver and the giver simultaneously.

- Shafi'is and the majority: This is not permissible, even with the principal's permission, because an agent cannot undertake both sides of a contract. - Hanbalis: It is permissible for an agent to receive from himself for himself, even in currency exchange (sarf), if the principal authorizes it.

To correct the transaction in the inquired scenario (transferring money to a brother through another person in a foreign country):

1. First solution (according to the Hanbali view): Transfer the amount to the person as a deposit, then authorize him to disburse it from himself (in his capacity as your agent), and he keeps the equivalent in your country's currency as a trust. 2. Second solution (preferable to avoid dispute): The person keeps the deposit in foreign currency, then your brother directly exchanges it with him upon his arrival at the exchange rate at that time. 3. Third solution (to guarantee the money): Lend this person the money, for a loan is guaranteed. Then, your brother receives it in your country's currency at the rate of the day of repayment, provided there is no prior agreement on this.