Wa`alaykum as-salamu wa rahmatullahi wa barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
Dear brother in Islam, thanks a lot for your question, which reflects your care to have a clear view of the teachings of Islam. Allah commands Muslims to refer to knowledgeable people to learn more about the teachings of Islam.
It is absurd for anyone to suggest that Islam advocates killing people who choose to leave Islam. To kill anyone who chooses to follow a religion other than Islam is against the fundamental teachings of the Qur’an. Freedom of conscience is a fundamental principle of the Qur’an that is clearly stated. Thus, if apostates cause no harm to the Muslim community and do not call for spreading hostility towards Islam, they should not to be punished; rather they should be advised kindly and wisely to learn the truth about Islam.
In his response to your question, Sheikh Ahmad Kutty, a senior lecturer and Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states the following:
Freedom of conscience is one of the fundamental rights of humans enshrined in the Qur’an; it is therefore, absurd for anyone to suggest that Islam allows putting people to death just because they convert to another religion.
Even a casual reader of the Qur’an will not fail to be impressed by its emphasis on the freedom of conscience as a cornerstone of its moral structure. To cite a few verses as follows:
[There shall be no compulsion in religion. Distinct has now become the right way from [the wayof] error: hence, he who rejects the powers of evil and believes in God has indeed taken hold of a support most unfailing, which shall never give way: for God is all-hearing, all-knowing] ( Al–Baqarah 2:256)
[If it had been your Lord’s will, all who are in the earth would have believed. Will you, then, force the people to become believers?] (Yunus 10:99)
[And if they surrender themselves unto Him (i.e. God), they are on the right path; but if they turn away – behold, thy duty (O Muhammad,) is no more than to deliver the message: for God sees all that is in [the hearts of] His creatures.] (Aal `Imran 3:20)
[Hence, pay heed unto God, and pay heed unto the Messenger, and be ever on your guard [against evil]; and if you turn away, then know that Our Messenger’s only duty is a clear delivery of the message [entrusted to him].] (Al-Ma’idah 5:92)
[But if they turn away [from thee, O Prophet, know that] Wehave not sent thee to be their keeper: thou art not bound to do more than deliver the message [entrusted to thee] .] (Ash-Shura42:48)
I should further state that all of the moral teachings of the Qur’an are based on the notion of moral responsibility, which entails the freedom of choice. Therefore, to state that one must be put to death for choosing to disbelieve would only undermine the entire moral edifice of the Qur’an.
Furthermore, the Qur’an does not allow anyone to harm those who are leaving in peace, no matter what religion they hold on to. This principle has been clearly stated in the Qur’an as follows:
[Thus, if they let you be, and do not make war on you, and offer you peace, God does not allow you to harm them.] (An-Nisaa‘ 4:90)
In pursuance of this policy, the Prophet (peace and blessings be upon him) issued clear directives to his soldiers never to disturb those who are engaged in any form of worship. The policy of living and letting others to live is firmly enshrined in the following verses:
[Say: O disbelievers! I do not worship what you worship, Nordo you worship what I worship. … to you your religion, and to me, mine.] (Al-Kafirun 109:1-3, 6)
In full conformity with the above teachings, neither the Prophet (peace and blessings be upon him) nor any of the four rightly guided caliphs who succeeded him were in the habit of hunting down people and executing them for merely changing their religions. Rather, they refrained from doing so except in rare cases involving treason. Treason, however, is another matter. The punishment for treason in the Qur’an is as strict as it is in the Hebrew Bible. But it must never be confused with mere change of religion.
In conclusion, it is absurd for anyone to suggest that Islam advocates killing people who covert to another religion.
Excerpted, with slight modifications, from Islam & Freedom of Belief
Allah Almighty knows best.