A commodity has intrinsic utility and may differ in quality, condition, location and usefulness. Money of the same denomination functions primarily as a medium of exchange; one Rs. 1,000 note does not become legally more valuable merely because it is newer than another Rs. 1,000 note.
This rule is especially important in financing because cost-plus sale (مرابحة) is valid only when the financing remains a real sale. The sequence of ownership, possession, risk and final sale must therefore be visible in the transaction.