Written by Dr. Ragheb Elsergany
Freedom of belief is one of the basics of Islam
In a clear and basic rule about the religious freedom and the freedom of expression in Islam, God Almighty says: “Let there be no compulsion in religion: Truth stands out clear from Error.” [Al-Baqara: 256]. The Prophet (PBUH) and the Muslims after him did not order anyone to compulsorily embrace Islam. Neither did they force people to look like Muslims to escape death or torture. How can they do this and they well know that if someone accepts Islam under duress, his Islam becomes valueless in the Doomsday, which every Muslim seeks to realize.
It was mentioned in the reasons behind the revelation of the aforementioned verse: Ibn Abbas said: “The women of the Helpers whose boys always died in infancy used to vow to bring up their boys as Jews if they were to live. When the Banu’l-Nadir were driven out, they had among them children of the Helpers. The Helpers said: ‘We will not leave our children!’ Upon which Allah, exalted is He, revealed: “Let there be no compulsion in religion: Truth stands out clear from Error.” 
Issue of faith, will of man
Islam has made the issue of faith or non-faith one of the issues that are dependant on man’s own will and his inner convictions. God Almighty says: “Let him who will believe, and let him who will, reject (it).” [Al-Kahf: 29] The Quran also has attracted the Prophet’s attention to this truth and told him that he is only responsible for calling people to Allah and he has no authority to convert them to Islam. He says: “Wilt thou then compel mankind, against their will, to believe!” [Yunus: 99] and said: “Thou art not one to manage (men’s) affairs” [Al-Ghashiyya: 22] and said: “If then they run away, we have not sent thee as a guard over them.” [Ash-Shura: 48]. Consequently, it becomes clear that the constitution of Muslims stipulates freedom of belief and categorically rejects compelling anybody to accept Islam.
Religious pluralism in Islam
Endorsement of religious freedom means admission of religious pluralism. This was a practical exercise when the Prophet (PBUH) admitted religious freedom in the first constitution of Medina, when he admitted that the Jews together Muslims form a one community. Also during the conquest of Mecca, the Prophet (PBUH) did not force Quraysh to accept Islam despite he was empowered and victorious. He told them: “Go you are free men”. Following his footsteps, Caliph Umar Ibn Al-Khattab offered Christian residents of Jerusalem protection for their lives, churches and crucifixes and that none of them should be harmed or forced to change his religion.
Islam even enshrined freedom of religious debating on objective bases away from altercations or mocking the other. In this regard, God Almighty says: “Invite (all) to the Way of thy Lord with wisdom and beautiful preaching; and argue with them in ways that are best and most gracious.” [Al-Nahl: 125] On these gracious principles, dialogue should be built between Muslims and non-Muslims. Islam has also called for dialogue with the people of the book. The Quran says: “Say: “O People of the Book! Come to common terms as between us and you: That we worship none but Allah. That we associate no partners with him; that we erect not, from among ourselves, Lords and patrons other than Allah. If then they turn back, say ye: “Bear witness that we (at least) are Muslims (bowing to Allah’s Will).” [Al’Imran: 64] This means that if dialogue renders no result, everybody then has his own religion that he convinced of and that was also expressed in the last verse of Al-Kafirun, which concluded with the Prophet (PBUH) saying: “To you be your Way, and to me mine.” [Al-Kafirun: 6]
1.Abu Dawoud: Kitab Al-Jihad (Al-Jihad Book), Chapter about prisoner forced to embrace Islam (2682), and look: Al-Wahidi: Reasons behind revelation of Quran p. 52, and Al-Siyuti chapter about revelation p. 37 and Al-Albani said: correct, see: sahih and Da’if in Sunnan Abu Dawoud 6/182