Jurisprudence Rules and their Applications in Codifying the Provisions of Islamic Financial Transactions

The study aimed to clarify the concept of the rule of "custom is firm" and the adoption of custom in matters that do not have a legal determination, as well as the sub-rules included within it, and to clarify its legal evidence, and to present its applications in Islamic financial transactions, as well as its applications in the accounts of Islamic banks. The study included a general definition of the rule of "custom is tight" and the meaning of custom is tight, then a statement of the concept of legalization and the necessity and importance of legalization in contemporary financial transactions, and what are its controls for legalizing contemporary financial transactions. The study concluded that there are contemporary applications of the rule of "the habit is court", by codifying the jurisprudential rules and also by adapting bank accounts in Islamic banks, where the study recommended the need to pay attention to studying the jurisprudence rules and codify the provisions of contemporary financial transactions because of their importance in the jurisprudential rooting of those contemporary transactions.