The Meaning and Scope of the Rule "Duration has a value"

The juridical rule or principle "duration has a value" is one of the most important jurisprudential principles applicable to transactions and issues such as the option of condition, murabahah sale, tawliyah, muwadha'ah sale, purchase on credit, options, futures or sale of things in advance, usury and loan. Nevertheless, two aspects of the subject e.g. the purport and scope of the rule, have received but very little attention. Two major probabilities with regards to the purport of the rule can be derived from the statements of the jurists. First, the dissimilarity between duration and price and consideration of a portion of the price against the duration in extended transactions. Second, the impact of duration on the amount of the price without them being in contrast with each other.  When it comes to the scope of the rule, a specific criterion has not been mentioned. In this article which uses an analytical descriptive method, the writer demonstrates that according to the rule, duration does have an impact on the amount of the price, and that there is a relationship between the duration and price.  As well, while seeking to present a criterion for explaining the scope of the juridical rule, it is demonstrated that the principle applies to that category of transaction which involves monetary profit or commercial gains. Thus, the principle applies to contracts like sale and lease where the two parties give something in exchange for something else. It is, therefore, not applicable to contracts likes loans. As well, this research will show that after a debt is established on the debtor, it is not permissible for the creditor to increase the amount of the debt, and that the principle of duration does not apply to debts.  It can be said, therefore, that there is objection to some scholars taking recourse to the rule in the area of loans.