The Quranic position on retaliation is natural to humankind and traditional to most existing cultures although their sacred doctrines might be ambigous or self-contradictory on the issue. To wit: an individual or a people should retaliate if attacked, but they should not start a fight.
One might reasonably presume that retaliation includes immediate self-defense. Self-defense abrogates guilt for murder and mayhem; as for organized, mass murder, theories of just war are based on the principle of self defense.
Proponents of war may argue that life not worth fighting for is not worth living, and that the end result of war is the moral progress of the human race, particularly when it is waged in the name of God. The regulation of murder and the division of spoils is at the foundation of many religious institions. Religion worships absolute power, while politics divides the spoils.
"Believers, retaliation is decreed for you in bloodshed; a free man for a free man, a slave for a slave, and a female for a female.... Men of understanding! In retaliation you have a safeguard for your lives; perchance you will guard yourselves against evil." (Quran, 2:178)
"Fight for the sake of God those that fight against you, but do not attack them first. God does not love the aggressors." (2:190)
There lived among the ancients certain persons who professed love for all humankind and who life one must kill for is not worth living. Hence they were foolish for love's sake and sacrificed their lives instead of defending them. They were roundly condemned by the warlords and their ministers, who often justified their own seemingly absurd logic by reference to "God's mysteries."
"Fighting is obligatory to you, much as you dislike it. But you may hate a thing although it is good for you, and love a thing although it is bad for you. God knows, but you do not." (2:216)
Woe on the pacifists who will not fight for Islam's one-god; are they not traitors hence infidels?
"Believers, do not follow the example of the infidels, who say of their brothers when they meet death abroad or in batttle: 'Had they stayed with us they would not have died nor would they have been killed.' God will cause them to regret their words.... If you should die or be slain in the cause of God, His forgiveness and His mercy would surely be better than all the riches they amass...." (3:156)
Furthermore, "Never think that those who were slain in the cause of God are dead. They are alive, and well provided for by their Lord."
The impious infidels - "God bears no love for the impious and sinful." (2:276) - however, shall have no reward in paradise:
"He that chooses a religion other than Islam, it will not be accepted from him and in the world to come he will be one of the lost." (5:84)
Of course seeking revenge for the sake of God is tantamount to following God's good example:
"Those that deny God's revelations shall be sternly punished; God is mighty and capable of revenge." (3:4)
Infidels can only hope that the principle of self-defense by retaliation is based on actual physical attacks and not on the usual trifles indignant human beings are all too willing to stake their lives on. St. Louis warned men not to kill people over words; of course, if they are infidels, he said, they should be run through with a sword.
"We will put terror into the hearts of the unbelievers. They serve other deities besides God for whom He has revealed no sanction. The Fire shall be their home; dismal indeed is the dwelling of the unbelievers." (3:147)
We find similar rhetoric repeated by Christian fundamentalists; but of course, for both faiths are rooted in Judaism, and the conservative fundamentalists of both persuasions are naturally frustrated Jews; or, rather, Hebrews, for Judaism is far more liberal than the tribe that practices lex taliones. Islam, however, is far more monotheistic than Christianity, and even more so than Judaism itself. A word from the wise: religious uniforms are not to blame for the strife.
We might wonder where the retaliation will end - only God knows when. No doubt it will forever cease in paradise. In which paradise, we cannot say for sure, at least not until the fat lady sings her last aria, or until Dr. Frankenstein's monster takes up exile on his ice floe.
"Farewell! I leave you, and in you the last of humankind whom these eyes will ever behold. Farewell, Frankenstein! If thou wert yet alive and yet cherished a desire of revenge against me, it would be better satiated in my life than in my destruction. But it was not so; thou didst seek my extinction, that I might not cause greater wretchedness; and if yet, in some mode unknown to me, thou hadst not ceased to think
and feel, thou wouldst not desire against me a vengeance greater than that which I feel. Blasted as thou wert, my agony was still superior to thine, for the bitter sting of remorse will not cease to rankle in my wounds until death shall close them forever.
"But soon," he cried with sad and solemn enthusiasm, "I shall die, and what I now feel be no longer felt. Soon these burning miseries will be extinct. I shall ascend my funeral pile triumphantly and exult in the agony of the torturing flames. The light of that conflagration will fade away; my ashes will be swept into the sea by the winds. My spirit will sleep in peace, or if it thinks, it will not surely think thus.
He sprang from the cabin window as he said this, upon the ice raft which lay close to the vessel. He was soon borne away by the waves and lost in darkness and distance. (1)
(1) Frankenstein or The Modern Prometheus, by Mary Shelley.