One of the problems that banks are facing is the problem of bank arrears. In recent years, due to the delay of the bank debtors in repaying the banks' resources and the accumulation of interest and fines, sometimes their debt was several times the original amount, therefore, by passing the law on facilitating the settlement of the debtors' debts of the country's banking network, the members of the parliament prohibited the receipt of compound interest, which Paying attention to the opposition of the Guardian Council was finally implemented with the approval of the Expediency Council, so it seems necessary to examine the arguments of the Guardian Council in rejecting this law. In this research, the necessary documents are collected by examining jurisprudence and legal books, and by referring to books and articles about bank fines, the proofs of the permissibility of compound interest are explained with a descriptive and analytical method. In this article, the evidences of each of those who believe that compound interest is permissible and the evidence of those who believe that it is not permissible have been examined, and Mukhtar's theory is that it is legal to receive damages for late payment based on legal rules such as the no-harm rule and the rule of conditions. Also, receiving compound interest is unimpeded according to the general rule of conditions. From the legal point of view, it is permissible to receive a fine for delay based on Articles 10 and 230 of the Civil Code. Also, there...