Freedom of speech or expression is the political right to express one's opinion or ideas. The right to freedom of expression is not absolute anywhere in the world, and is subjected to restrictions as with slander, sedition, libel, obscenity, etc. In an Islamic Republic, no one is allowed to spread immorality or broadcast obscenity in the name of freedom of media or press. No one is allowed to calumniate the innocent under the pretext of freedom of speech. Regarding the speech or expression, the Quran gives several guidelines such as: talking straight without any deception; choosing best words to speak and saying those in the best possible manner; speaking politely; shunning false and deceitful statements; not confounding truth with falsehood; using civilized language; and being just when voicing an opinion.
The Quran also gives guidelines for those who are at the receiving end of the information. It says: when you hear something malicious about someone, keep a favorable view about him/her until you attain full knowledge of the matter. It enjoins to consider others innocent until they are proven guilty with solid and truthful evidence. It urges to ascertain the truth of any news, lest you smite someone in ignorance and afterwards repent of what you did. It forbids following blindly any information of which you have no direct knowledge; using your faculties of perception and conception you must verify it for yourself; in the court of your Lord, you will be held accountable for your hearing, sight and faculty of reasoning.
One is absolutely free to express his/her opinion or ideas as long as these are not against the 'just requirements of morality, public order or general welfare'. The Quran commands the Muslims not to use abusive, insulting or defamatory language even against the deities worshipped by the non-muslims. Freedom of speech should not lead to inciting violence or hatred among people, or divulging classified secrets of the state. The Quran mentions many prophets which were abused or mocked at by their contemporaries as being foolish, liars, possessed or fabricators but all of Allah's Prophets responded with compassion, mercy and clemency and never took personal revenge. The last Messenger of Allah was compassionate and merciful not only for the believers but for all the humanity. It is not right for the authorities of the Islamic Republic to curb fair criticism on their policies and genuine differences of opinion. Anyone who suffers any injustice has full right to publically criticize those in authority but those who have not suffered any injustice cannot be allowed to spread malicious propaganda without any reason.