Is it obligatory to repay gold with gold, or is its value in cash permissible when settling a debt?

The principle is that a debt is repaid in kind. So, whoever borrows gold repays it with gold of the same kind. If the debt is in cash, it is not permissible to agree at the time of lending to repay it with a different currency at a later time, due to the condition of immediate exchange in currency transactions (sarf). In this matter, it is permissible for the borrower to repay the gold with its cash value, because currency exchange for a debt that is due is like currency exchange for something in hand, and it is permissible to demand one currency in exchange for another. This is supported by the hadith of Ibn Umar: "There is no harm in taking it at the price of its day, as long as you do not separate while there is still something between you."