The constitution of Iran defines the country as an Islamic republic and designates Shia Islam as the official state religion. The constitution stipulates that all laws and regulations must be based on “Islamic criteria” and an official interpretation of sharia.
The constitution states that citizens shall enjoy all human, political, economic, social, and cultural rights “in conformity with Islamic criteria.” The constitution also prohibits the investigation of an individual’s ideas and states that no one may be “subjected to questioning and aggression for merely holding an opinion.” The law prohibits Muslims from changing or renouncing their religious beliefs.
The only recognized conversions are from another religion to Islam. Conversion from Islam is considered apostasy, a crime punishable by death. Under the law, a child born to a Muslim father is Muslim. By law, non-Muslims may not engage in public persuasion or attempted conversion of Muslims.
These activities are considered proselytizing and punishable by death. Terrible as it is, Iran’s penal code has serious flaws. For one, all these provisions I just mentioned are easy to manipulate and have been manipulated countless times.
The penal code allows judges to rely on non-codified law to convict and sentence individuals to crimes and punishments. For example the law explicitly allows judges to rely on religious sources, including shari’a and fatwas issued by high-ranking Shia clerics, to convict an individual of apostasy or to sentence a defendant convicted of adultery to stoning.