Hadith 698

Narrated 'Ubadah bin as-Samit (RA): Allah's Messenger (ﷺ) said: "Gold is to be paid for with gold, silver with silver, wheat with wheat, barley with barley, dates with dates, and salt with salt, same quantity for same quantity and equal for equal, hand to hand (i.e. payment being made on the spot). If these classes differ, sell as you wish as long as payment is made on the spot." [Reported by Muslim].