Conditions for the Permissibility of Selling Gold for Gold or for Currency

Question:
May Allah reward you. Honorable Shaykh, he says: I have been buying and selling gold for more than twenty years. These shops of mine, O Honorable Shaykh, I deal with people in buying and selling gold through the network, and I also offer installment payments through the network.

Answer:
My brother, selling currency, selling gold for gold or for silver, or currency for currency, this is called sarf (currency exchange). It requires immediate exchange of possession. If the two types are the same, they must be equal in amount, and immediate exchange of possession is required. If the types differ, difference in amount is permissible, but immediate exchange of possession in the meeting is obligatory. It is not permissible for them to separate from the meeting with anything between them, and there is no installment, no deferral, and no delay. He says, "I will go home, look, and give you the value." No, it is not permissible. They must not separate with anything between them, as in the hadith: If he sold it for something other than currency, sold it for something other than gold and other than currency, sold it for cloth, livestock, or cattle, something other than its type, sold it for something other than currency and other than gold or other than silver, then he may delay and he may defer. Yes.