The value of a currency may rise or fall in relation to gold and silver, which are regarded as the standard against which the prices and values of things are measured, and prices are determined on that basis. This is what the Fuqaha refer to when they speak in this context of rise and fall in value. What matters with regard to paying off debt that are confirmed in a particular currency is that they should be paid off in that currency, not on the basis of value, because debts are to be paid exactly as they are; it is not permissible to connect a fixed debt to the price of things (inflation), regardless of how the debt came about.