The principle is the bindingness of contracts, and lease is also considered a binding contract. However, in some cases, an unforeseen phenomenon such as hyperinflation can disrupt the economic equilibrium of the counter-values (ʿiwaḍayn) to such an extent that continued performance of the contract becomes extremely difficult (ʿusr wa ḥaraj) for one of the parties. The main issue of this research is to analyze the foundations of rent adjustment under inflationary conditions and its relationship with the principle of contractual bindingness.

Using a descriptive-analytical method, this study re-examines the jurisprudential nature of money based on the theory of "conventional value" (al-māliyyah al-iʿtibāriyyah) emphasized by contemporary jurists such as Ayatollah Mousavi Bojnūrdī. It analyzes secondary rules, including the "negation of hardship" (qāʿidat nafy al-ʿusr wa al-ḥaraj), alongside the capacities of the "implied condition of equilibrium" and the authority of the ruler in the "region of discretion" (mintaqat al-farāgh), drawing on the jurisprudential foundations of Imam Khomeini regarding the expediency of the system (maṣlaḥat al-niẓām).

The findings indicate that hyperinflation is better analyzed under the concept of hardship rather than force majeure. When hyperinflation causes ʿusr wa ḥaraj, secondary rules enable judicial or legal adjustment of the contract. The implied condition, rational custom (al-bināʾ al-ʿuqlāʾī), and the ruler's discretionary powers also play a complementary role in justifying such intervention.

The innovation of this research, aimed at regulating judicial interventions, is the design of a "four-step tiered model" (including customary risk, renegotiation, judicial adjustment, and emergency intervention by the ruler), which provides an operational framework for moving beyond the dichotomy between absolute contractual bindingness and ad-hoc, unregulated interventions.