This research aims to explain the role of the jurisprudential rule of no harm as the basis for criminalizing crimes against public security and peace in the criminal laws of Iran and Afghanistan, using a descriptive-analytical and comparative method, and answers the question of how this rule has been crystallized in the criminal laws of the two countries as the basis for criminalizing crimes against public security and peace. The findings of the research show that the rule of no harm, based on the prophetic hadith "no harm and no harm" and the Quranic, rational and consensus support, has been the fundamental principle and the basis for legitimizing numerous criminalizations in both legal systems. Examples of this influence in the laws in question include environmental crimes, the dissemination of criminal cyber content, the dissemination of lies, forgery, arms and drug trafficking, computer crimes, and serious crimes such as war and corruption on earth. The purpose of these criminalizations is to avert harm and prevent individual and social harm that threatens security, comfort, health, and public order. Finally, this research shows that the no-harm rule has a function beyond civil rights and, as a reasoned and dynamic standard, has provided Iranian and Afghan legislators with the necessary capacity to respond to emerging threats such as cybercrime.