Contract Adjustment and Its Application in Islamic Jurisprudence and Iranian Law

Despite the universal recognition of the principle of pacta sunt servanda (the binding nature of contracts) across all legal systems and the necessity of honoring mutual consent, the influence of unforeseen social and economic developments occurring between the conclusion and performance of a contract is undeniable. Within the framework of contractual freedom, the doctrine of contract adjustment allows for rescission or modification in cases where unforeseeable events lead to fundamental changes in the circumstances existing at the time of contract formation, thereby causing undue hardship or excessive loss to one of the parties. In Iranian law, contract adjustment holds a prominent position, having been extensively discussed by jurists and legal scholars. Various forms of adjustment—including contractual, statutory, and judicial adjustment—serve as effective tools for resolving difficulties in the execution of contracts. The primary objective of contract adjustment is to promote fairness in contractual relations, safeguard public interests, and protect the aggrieved party. According to the findings of this study, the concept of contract adjustment is acknowledged in both national legislation and Islamic jurisprudence. This is due to the principle of contractual freedom, which permits the inclusion of any valid condition within a contract. In Shi'a jurisprudence and Iranian law, contract adjustment is permissible by invoking various jurisprudential doctrines such as the principles of “no hardship and constraint” (la ḥaraj), “supervening inequity” (ghabn-e-ḥādeth), “implied terms,” and “public interest” (maṣlaḥa), each of which is grounded in the Qur’an, the Sunnah, scholarly consensus, and reason.