Sayyiduna Ubadah bin Samit (may Allah be pleased with him) narrates that the Noble Prophet (peace and blessings be upon him) said:“Gold for gold, silver for silver, dates for dates, wheat for wheat, barley for barley, and salt for salt can only be sold in equal amounts, hand to hand. But when these types differ, then sell as you wish, as long as it is hand to hand (i.e., not on credit).”