A reflection on the criminal laws in time with emphasis on ijtihadi verdicts

One of the basic principles of modern criminal law is non-retroactivity of substantive laws. This principle is also one of the accepted principles of the criminal law of the Islamic Republic of Iran. However, some exceptions have been made؛ one of these is the sharia laws that always have retroactive effect. But apart from the Shari'a law, there are many substantive criminal judgments based on the fatwa of the jurists, which are based on Ijtihad reasons and they are not based on consensus and often controversial. In these cases, the legislator's approach is to adopt one of the fataw which is considered as an apparent religious judgment. Sometimes this fatawa changes due to pathology and time requirements at the stages of law reform. In this research, the approach of the Islamic punishment legislator and Imamiyah jurisprudents to the exclusion of criminal law based on the Islamic jurisprudence of ijtihadi from the principle of non-retroactivity.