Abstract

The theory of difficulty in execution of contract (which deals with specific conditions created in the course of implementing the contract), as a new theory in the world of law, has some similarities to the rule of rejection of hardship and suffering (usr wa haraj), which is considered as a secondary rule governing primary rules. They are similar in terms of the application of the rule in the contracts and the results which are obtained from invoking the theory of difficulty and the implementation of hardship and suffering rule. First, because there is a same reason for invoking them that is implementation of the provisions of a forcible contract, a contract that its implementation is not impossible but it entails intolerable hardship for the engaged person, in a manner that it is possible to continue the commitment but it is injustice to persist on the enforcement of the contract, and in different cases in order to avoid injustice one can resort to the rule of the rejection of hardship and suffering or the theory of difficulty, and perform the contract in a different way. Second, because in both rules the affected person is given the right of adjustment or termination of the contract and conditions will be provided to get him free from the unjust and intolerable conditions. Then, we can say that although the rule of the rejection of hardship and suffering and the theory of difficulty are different in some aspects, they conform to each other in terms of the mentioned cases.

Key words: Theory of difficulty, The rule of hardship and suffering, Termination, Adjustment, Execution of the contract.