To what extent is the hadith authentic: “Gold for gold, silver for silver, wheat for wheat, barley for barley, dates for dates, and salt for salt,” and that the exchange be hand-to-hand (ha’ bi ha’), and what is the ruling on buying and selling these items according to Sharia?

Muslim narrated from 'Ubadah ibn al-Samit that the Prophet, peace and blessings be upon him, said: "Gold for gold, silver for silver, barley for barley, dates for dates, salt for salt, like for like, equal for equal, hand to hand. If these types differ, then sell as you wish, provided it is hand to hand." The 'illah (underlying cause) of riba in gold and silver is their monetary value (thamanīyah), and in the rest, it is edibility combined with measurement by volume (kayl) or weight (wazn). Accordingly, there are different scenarios for selling and buying ribawiyyat (items subject to riba):

1. Selling an item for another of the same kind (e.g., dates for dates): Both equality (tamāthul) and immediate possession (taqābuḍ) are required.

2. Selling an item for another of a different kind but sharing the same 'illah (e.g., gold for silver): Immediate possession (taqābuḍ) is required, but equality (tamāthul) is not.

3. Selling an item for another of a different kind and not sharing the same 'illah: Neither immediate possession (taqābuḍ) nor equality (tamāthul) is required.