Is my work in currency exchange between Saudi Arabia and Sudan—taking a fixed amount for every thousand Saudi Riyals, sometimes experiencing delays in receiving the money, and having a varying exchange rate between cash and bank transfers—considered a form of usury (riba)?

Exchanging Saudi Riyals for Sudanese Pounds is considered a currency exchange (sarf), which requires immediate possession (taqabud) at the time of the contract, either actually or constructively. Delaying the receipt for a day or two is not permissible, and recording it in ledgers does not constitute constructive possession.

The Messenger of Allah (peace be upon him) said: "Gold for gold, silver for silver, like for like, equal for equal, hand to hand. If these types differ, then sell as you wish, provided it is hand to hand."

Contracts made over the phone are valid for transactions that do not require immediate possession. However, for transactions that do require immediate possession, they are only valid if possession takes place immediately after the conversation ends. One must avoid such transactions due to their lack of adherence to Sharia regulations and because the law may not permit them.