This article is intended to show that Islam recognises complete freedom of religion and belief for every human being, and that, consistently with this principle, it does not prescribe any punishment whatsoever for a person who leaves the religion of Islam to adopt some other faith.
The Holy Quran altogether excludes compulsion from the sphere of religion. It lays down in the clearest words:
In fact, the Holy Quran is full of statements showing that belief in this or that religion is a person’s own concern, and that he is given the choice of adopting one way or another. If he accepts the truth, it is for his own good, and that, if he sticks to error, it is to his own detriment. Some quotations to this effect are given below:
“The Truth is from your Lord; so let him who please believe and let him who please disbelieve.”  18:29
“Clear proofs have indeed come to you from your Lord: so whoever sees, it is for his own good; and whoever is blind, it is to his own harm. And I am not a keeper over you.”  6:104
The duty of the Messenger of Allah, and, following him, the duty of every Muslim is only to deliver the message of truth and no more. This is indicated in the Holy Quran in passages of the following kind:
If they accept Islam, then indeed they follow the right way; and if they turn back, your duty (O Prophet) is only to deliver the message.  3:20
And obey Allah and obey the Messenger; but if you turn away, the duty of Our Messenger is only to deliver the message clearly.  64:12; see also 5:92
Say (to people): Obey Allah and obey the Messenger. But if you turn away, he is responsible for the duty imposed on him, and you are responsible for the duty imposed on you. And if you obey him, you go aright. And the Messenger’s duty is only to deliver (the message) plainly.  24:54
O people, the truth has indeed come to you from your Lord; so whoever goes aright, goes aright only for the good of his own soul; and whoever errs, errs only to its detriment. And I am not a custodian over you.  10:108
Surely We have revealed to you (O Prophet) the Book with truth for people. So whoever follows the right way, it is for his own soul, and whoever errs, he errs only to its detriment. And you are not a custodian over them.  39:41
We have not appointed you (O Prophet) a keeper over them, and you are not placed in charge of them.  6:107
Your duty (O Prophet) is only the delivery of the message, and Ours (Gods) is to call (people) to account.  13:40
The Quran tells us that it is in the natural order of things that while some people believe others do not, and no human being can or should apply compulsion to others in this regard. The Holy Prophet Muhammad is told:
And if your Lord had pleased, all those who are in the earth would have believed, all of them. Will you then force people till they are believers?  10:99
For everyone of you We appointed a law and a way. And if Allah had pleased He would have made you a single people (or one religious community), but that He might try you in what He gave you. So vie one with another in virtuous deeds. To Allah you will all return, so He will inform you of that wherein you differed.  5:48
Muslims are allowed in certain circumstances to wage war. Every student of Islamic history knows that the Holy Prophet and his companions were subjected to the severest persecution, as Islam began to gain ground at Makka; over a hundred of them fled to Abyssinia, but persecution at home grew still more relentless. Ultimately, the Muslims along with the Holy Prophet had to take refuge in Madina, but they were not left alone even there, and the sword was taken up by the enemy to annihilate Islam and the Muslims. It was at that juncture that the Quran permitted them to fight:
“Permission (to fight) is given to those on whom war is made, because they are oppressed. And Allah is able to assist them — those who are driven from their homes without a just cause except that they say: Our Lord is Allah.”  22:39, 40
Thus the object of allowing the Muslims to fight was not to compel the unbelievers to accept Islam, for it was against all the broad principles in which they had hitherto been brought up. No, it was to establish religious freedom, to stop all religious persecution, to protect the houses of worship of all religions, mosques among them. The above passage continues as follows:
“And if Allah did not repel some people by others, then cloisters and churches and synagogues and mosques in which Allah’s name is much remembered, would have been pulled down.”  22:40
Thus Muslims are permitted to undertake war not only to stop their own persecution and to save their own mosques, but to save churches and synagogues as well; in fact, to establish perfect religious freedom. They are allowed to fight only those who fight against them, and to stop when the persecution ceases:
“And fight in the way of Allah against those who fight against you, but be not aggressive. Surely Allah loves not the aggressors.”  2:190
“But if they desist, then surely Allah is Forgiving, Merciful. And fight them until there is no persecution, and religion is only for Allah.”  2:192193
There should be no persecution on the score of religion and everyone must be at liberty to hold any belief he likes. The words religion is only for Allah or all religions are for Allah carry the significance that religion is a matter between man and his God, a matter of conscience, in which nobody has a right to interfere.
The Holy Prophet made treaties of peace with his enemies; one such treaty brought about the famous truce of Hudaibiyah, the terms of which were disadvantageous to the Muslims. According to the terms of this treaty “if an unbeliever, being converted to Islam, went over to the Muslims, he was to be returned, but if a Muslim went over to the unbelievers, he was not to be given back to the Muslims”. This clause of the treaty cuts at the root of all allegations of the use of force by the Holy Prophet.
If anyone of the idolaters seek your protection, protect him till he hears the word of Allah, then convey him to his place of safety. This is because they are a people who have no knowledge.  9:6
The explanation of this verse, as given in a classical Arabic commentary of the Quran written over a thousand years ago, is as follows:
 Then convey him to his place of safety means return him, after he has heard the word of Allah, if he refuses to accept Islam and is not admonished by the word of God that is read to him, to his place of safety, that is to say, to a place where he is safe from you and your followers, until he reaches his abode and joins his people, the idolaters. (Tafsir Ibn Jarir)
George Sale, who produced the first English translation of the Quran directly from Arabic in the 18th century, and was a hostile critic of Islam, explains the meaning of this verse as follows in his footnote on this verse:
You shall give him a safe conduct that he may return home again securely in case he shall not think fit to embrace Muhammadanism.
What greater tolerance could there be than this, that an enemy soldier, on his request, is to be granted protection while he learns about Islam, and if he chooses not to accept it, Muslims must conduct him securely to his place of origin, where he is safe from Muslims and rejoins the very enemies whom the Muslims are fighting!
It is sometimes asserted that the Quran forbids relations of friendship with the followers of other religions. The fact is that, wherever there is prohibition against making friends with other people, it relates only to the people who were at war with the Muslims, and this is plainly stated in the Quran:
“Allah does not forbid you as regards those who do not fight you for religion, nor drive you forth from your homes, that you show them kindness and deal with them justly. Surely Allah loves the doers of justice. Allah forbids you only as regards those who fight you for religion, and drive you forth from your homes and help (others) in your expulsion, that you make friends of them; and whoever makes friends of them, these are the wrongdoers.”  60:8, 9
It is generally thought that Islam provides a death sentence for those who desert the religion of Islam. Anyone who takes the trouble to read the Quran will see that there is not the least ground for such a supposition.
1. Several times the Quran speaks of people going back to unbelief after believing, but never once does it say that they should be killed or punished. In one place the Quran refers to the war being made upon Muslims by their opponents based in Makka and says:
“They will not cease fighting you until they turn you back from your religion, if they can. And whoever of you turns back from his religion, then he dies while an unbeliever — these it is whose works go for nothing in this world and the Hereafter.”  2:217
This verse clearly speaks of a person as continuing to live after turning away from the religion of Islam until he dies while still an unbeliever. This verse also shows that force was being used against Muslims by their enemies to make them leave Islam, rather than being used by Muslims to keep the followers of Islam within its fold.
“O you who believe, should anyone of you turn back from his religion, then Allah will bring a people whom He loves and who love Him.”  5:54
“Those who disbelieve after their believing, then increase in disbelief, their repentance is not accepted, and these are they that go astray.”  3:90
Those who believe then disbelieve, again believe and again disbelieve, then increase in disbelief, Allah will never forgive them nor guide them in the (right) way.  4:137
The last verse above speaks of certain people who switched back and forth between Islam and unbelief. They embraced Islam of their own accord, then left it of their own accord, then came back of their own accord, and finally left it and became confirmed in disbelief. No punishment was applied to them at the hands of the Muslims, nor prescribed to be applied. Only God would judge them.
3. The Quran also speaks of a plan of a group of Jews living in Madina to adopt Islam first and then desert it, thus creating the impression that Islam was not a religion worth having:
And a party of the People of the Book say: Avow belief in that which has been revealed to those who believe, in the first part of the day, and disbelieve in the latter part of it, perhaps they may turn back.  3:72
Such a scheme, that they would first announce belief in Islam and then renounce it a little later, could never have been conceived by them while living at Madina, where the Government was Muslim, if apostasy, according to the Quranic law, were punishable with death.
4. In the Encyclopaedia of Islam, which is a production of a number of non-Muslim Western orientalists, it is stated at the beginning of the article Murtadd (Apostate) written by Willi Heffening:
The misconception that apostasy is to be punished with death seems to have arisen from the fact that people who, after becoming apostates, joined the enemy, were treated as enemies, or that, where an apostate took the life of a Muslim, he was put to death, not for changing his religion, but for committing murder.
The Holy Quran mentions a number of kinds of people who leave the cause of Islam during war (4:8891), and instructs Muslims how to deal with each kind of case. Those who openly join the enemy, with whom the Muslims were at war, and fight against Muslims, should be fought in the same way as the enemy. Some other groups are mentioned as follows:
those who join a people between whom and you there is an alliance, or who come to you, their hearts shrinking from fighting you or fighting their own people.  So if they withdraw from you and do not fight you, and offer you peace, then Allah allows you no way against them.  4:90
Thus even in case of war, if anyone leaves the Muslim side but joins another non-Muslim people that the Muslims are at peace with, or he does not fight at all, then Muslims cannot harm him in any way.
The view that apostasy is punishable with death is derived by classical Islamic jurisprudence from various reports in books of Hadith. It should be noted that rulings in the books of jurisprudence are judgments arrived at by human beings and therefore cannot be treated as infallible.
However, even a careful study of Hadith leads to the conclusion that apostasy was not punishable unless combined with other circumstances which called for punishment of offenders, such as joining with the enemies with whom Muslims were at war. In any event, a Hadith report cannot be used to overturn principles clearly laid down in the Quran. A report such as Whoever changes his religion, kill him must be treated subject to the principle that the change must be accompanied by some crime committed against the Muslim community.
The books of Fiqh seem to recognise that mere change of religion is not punishable in Islam, but consider that the apostate thereby necessarily places himself in a state of war with the Muslims and thus should be killed as a combatant. On this ground the famous book of jurisprudence, Hidaya, rules that a woman apostate cannot be put to death for the reason that she is not able to fight in war against Muslims. It also contains the following statements: The killing for apostasy is obligatory in order to prevent the mischief of war, and it is not a punishment for the act of unbelief, and: “For mere unbelief does not legalize the killing of a man”. The jurists have committed a clear error, and contravened the Holy Quran, by considering that a Muslim who leaves the religion of Islam has necessarily joined those who are at war with Muslims.
If the Holy Quran and the practical actions of the Holy Prophet Muhammad are regarded as the supreme authorities for determining the teachings of Islam, then it is undeniable that Islam grants complete freedom to everyone to adopt whatever religion they wish, and does not allow Muslims to apply any punishment whatsoever to someone who leaves Islam.
This article is based on, and borrows from, the following authoritative writings by Maulana Muhammad Ali, and further expands upon the material in these sources.
The English Translation of the Holy Quran with commentary (in particular the section Liberal View of Other Religions in the Introduction), 1951.