Sanction of Condition of Legal Performance

Proviso is divided into three groups: provision, condition of description,and condition of corollary. Provision is, in turn, divided into two groups:1. material condition of performance (for example repairing an automobile) or non-performance (for example not building a storey above the existing storeys); 2. legal condition of performance (for example, selling the subject to a certain person or the release of someone from a debt) or legal condition of non-performance (such as not selling the subject to a certain person).The main theme of the present article concerns juridical and legal doctrines about legal intervention which are in conflict with the legal condition of performance. In other words, it concerns sanction for legal performance. Thus, condition of description, condition of corollary, and material condition of performance are out of the scope of the present article. The main question is "what is the legal impact of such a condition from a juridical and legal viewpoint?" Should, in this regard, general rules of sanction for refusal of condition of performance be executed? Or, for such conditions, particular sanctions should be considered?Concerning interventions which are in conflict with the condition of performance, there are three ideas: "nullity", "validity" and "invalidity". The present article puts emphasis on the third idea. To do so, at first, the author will go to discuss such interventions according to Shii jurisprudence, and then on the basis of Iranian legal system.