One of the fundamental principles of contract law is the principle of necessity, which is rooted in jurisprudence. Although the status of permissibility or necessity of certain contracts is specified in jurisprudence and civil law, considering the acceptance of the theory of non-preclusion of contracts and the principle of freedom of contract in jurisprudence and Article 10 of the Civil Code, the existence of the principle of necessity in the legal and jurisprudential structure is necessary, contrary to what is sometimes said. The incomplete reflection of the principle of necessity and a kind of confusion between the mandatory and conditional provisions in Article 219 of the Civil Code has caused some disputes. The most important drawback of the aforementioned article is that it deals with three important principles of contract law at the same time: the principle of necessity of contracts, the principle of the obligation of the execution of the contract, and the principle of the relativity of the effects of the contract. Some jurists have interpreted the principle of necessity as the necessity of the contract and have commented on its flow in mandatory and permissible contracts. Although the core of this principle is where the necessity and permissibility of a contract are in some way questionable, the present study seeks to present a new and expanded concept of the principle of necessity, expanding its scope to three other areas: contracts whose necessity is certain, permissible contracts, and iqā'at. This new concept, which can be interpreted as the "principle of the permanence of legal acts" or the "principle of the irrevocability of legal acts," is useful in both legal discussions (arbitral doubts about the principle of necessity) and judicial discussions (subjective doubts about the principle of necessity).