Both extremist fundamentalists and Islamaphobes like to use this passage to prove that the Koran requires that apostates should be killed.
They desire that you should disbelieve as they have disbelieved, so that you might be (all) alike; therefore take not from among them friends until they fly (their homes) in Allah's way; but if they turn back, then seize them and kill them wherever you find them, and take not from among them a friend or a helper. (4:89)
This is not, however, the only interpretation accepted by orthodox Muslims. Osama Abdallah attacks this interpretation at great length on his website www.answering-christianity.com and also cites several orthodox Islamic scholars as rejecting this interpretation. His response is based partly on Dr. Munir Munsey’s translation, which clarifies that the quote refers, not to apostates, but to hypocrites.
The hypocrites wish that you would reject faith just like they have. Then, you will (descend down to their level and) be equal to them. Therefore, do not choose them as friends unless they (emigrate and) leave their homes in the path of Allah. If they revert (to open hostility), then seize and slay them wherever you see them. Do not take them as friends or protectors, nor as helpers. (4:89)
The hypocrites are explicitly mentioned in the previous sura, so there is no question that they are the ones being discussed here. According to Abdallah, the hypocrites referred to in the quote were Jewish and Christian Arabs who pretended to convert to Islam for a while, then left and rejoined their own tribes. This would mean the people being discussed are not people who changed their minds and decided to leave Islam, but rather people who PRETENDED to convert to Islam. At the very least, this means that the injunction cannot apply people who were born Muslims and decided to convert to another religion. But more importantly, it does not refer to anyone who sincerely believes that they should convert to another religion. Consequently, this verse is fully consistent with the famous passage that says “Let there be no compulsion in religion.”
Abdallah says that these Jewish and Christian Arabs pretended to convert to Islam so they could make the religion look bad when they left. But I think a more likely explanation is that they were spies trying to gather military information. It is important to remember that the word ‘Muslim’ in the Koran refers to a small community under constant aggressive military attack. At that time, leaving Islam didn’t mean going down the street to another place of worship. It meant joining another army that was actively trying to kill Muhammad’s people. How would an American general in World War II respond to a soldier in his battalion who had joined the Nazis? Wouldn’t the most likely response be to have him shot?
However, Muhammad’s response was in fact much more lenient that my hypothetical general. The two passages that come immediately after this one show that this quote has been taken radically out of context.
Except for those (hypocrites) who find refuge with a nation with whom you have a treaty! Or unless they come to you such that their hearts cringe and neither allow them to fight you, nor their own people. Had Allah willed, He would have given them power over you, and they would have fought you. Therefore, if they stay aloof and do not fight you, or if they make overtures of peace, then Allah has given you no reason to commit aggression against them. (4:90) (My emphasis)
You will find other hypocrites who seek to stay safe from you, as well as from their people. But, (as soon) as they are tempted with a lure, they plunge headlong into mischief. If they do not stay neutral, and do not make overtures of peace towards you, and do not restrain their hands, then seize and slay them wherever you see them. In their case, we have given you a clear sanction. (4:91)
The first passage gives exceptions to the rule for killing hypocrites, which clearly show that if the hypocrites don’t cause trouble, they should not be hunted down and killed. If they are far away in another non-aggressive country, or if they have surrendered, or if they are not aggressively attacking Muhammad’s community, they should be ignored. The second passage does advise caution in dealing with the hypocrites who are still living within that community. But it also reiterates (in the contrapositive) the previous passage’s admonition that the hypocrites should be killed only if they are actively aiding the community’s enemies.
Thus the so-called “death to apostates” sura does not refer to sincere apostates at all, and does not advocate death except as a response to violent aggression. It’s amazing what taking a quote out of context can do.