The Book of Musaqah - Sahih Muslim 1588 d

Let dinar be exchanged for dinar, with no addition on either side and dirham be exchanged for dirham with no addition on either side.

Commentary on the Prohibition of Riba al-Fadl

This noble hadith establishes one of the fundamental principles regarding the prohibition of riba (usury/interest) in Islamic commercial transactions, specifically addressing what scholars term "Riba al-Fadl" - the excess in exchange of specific commodities.

The Prophet (peace be upon him) explicitly forbids any disparity in the exchange of gold for gold (dinars) or silver for silver (dirhams), mandating that such transactions must be equal in weight and hand-to-hand (spot transaction). This prohibition extends to all commodities that serve as monetary standards.

Legal Implications and Wisdom

Scholars derive from this that the six commodities mentioned in other narrations (gold, silver, wheat, barley, dates, salt) when exchanged for their own kind, require equality in measure and immediate exchange to avoid riba.

The divine wisdom behind this prohibition includes preventing exploitation, ensuring fairness in trade, and closing all avenues that lead to the greater riba (Riba al-Nasi'ah). This ruling protects the vulnerable from hidden usury disguised as legitimate exchange.

Contemporary Application

In modern contexts, this ruling applies to currency exchange where same currencies are traded, requiring equal value and immediate settlement. Paper money is generally treated analogous to gold and silver in contemporary fiqh rulings.

Muslims must exercise caution in financial transactions to ensure compliance with these divine guidelines, seeking halal earnings and avoiding any form of usurious practice, however subtle it may appear.