‘Ubada b. as-Samit reported God’s Messenger as saying, “Do not sell gold for gold, or silver for silver, or wheat for wheat, or barley for barley, or dates for dates, or salt for salt except equal for equal, kind for kind, payment being made on the spot; but sell gold for silver, silver for gold, wheat for barely, barley for wheat, dates for salt and salt for dates, payment being made on the spot, as you wish.”
Shafi'i transmitted it.