Lex talionis: The "law of retaliation," whereby a punishment resembles the offence committed, in kind and degree; an eye for an eye, a tooth for a tooth.
Let us keep in mind that the sad and shocking events in London are but small recompense (so to speak) for the tens of thousands of innocent civilians killed by US and UK forces in Iraq and Afghanistan. The human race has yet to learn that vengeance, whether it is called "justice," "just war," or "jihad," can never bring the emotional resolution or peace it promises. Tony Blair is right: the terrorists will never win, but neither will he as long as he employs violence. It is a fantasy to believe that violence can stop violence. The reality is that "an eye for an eye makes the whole world blind."
"You have heard that it was said, "An eye for an eye and a tooth for a tooth.' But I say to you, Do not resist an evildoer. But if anyone strikes you on the right cheek, turn the other also; and if anyone wants to sue you and take your coat, give your cloak as well; and if anyone forces you to go one mile, go also the second mile. Give to everyone who begs from you, and do not refuse anyone who wants to borrow from you.
"You have heard that it was said, "You shall love your neighbor and hate your enemy.' But I say to you, Love your enemies and pray for those who persecute you, so that you may be children of your Father in heaven; for he makes his sun rise on the evil and on the good, and sends rain on the righteous and on the unrighteous. For if you love those who love you, what reward do you have? Do not even the tax collectors do the same? And if you greet only your brothers and sisters, what more are you doing than others? Do not even the Gentiles do the same? Be perfect, therefore, as your heavenly Father is perfect.
—Matthew 5:38-48
Another thing to take note of is that the lex talionis, far from instituting retaliation as a duty (hardly necessary considering human nature), was meant to put a lid on retaliatory violence, which has a tendency to get out of proportion. We need look no farther for an example of this than the current "war on terror." Less than 3000 were killed in the September 11th attacks, and yet around 100,000 people have been killed in response, and two entire countries have been bombed into disordered and degraded living conditions. It is a sad comment on humanity's lack of development over the last 3500 years that the lex talionis would still be an improvement over the status quo. Perhaps it is not realistic to expect humans to only partially indulge their desire for retaliation. It may actually be more practical for us to abandon vengeance entirely, as Christ taught, and seek no satisfaction ourselves.
Beloved, never avenge yourselves, but leave room for the wrath of God; for it is written, "Vengeance is mine, I will repay, says the Lord."
—Romans 12:19
That is not to say that we should do nothing. People do not commit these sort of acts without reason. Though violence can never be justified or excused, its underlying causes must be recognized and rectified. The "Make Poverty History" campaign has rightly called on the G8 countries to rectify its economically unjust relations with Africa. The terrorists, in their misguided way, are also calling on the G8 to rectify their past and present unjust relations with many parts of the Muslim world. Let's stop pretending not to understand their pleas just because they use language we don't like. Even their ignorance and prejudice is a plea for education and honest exchange. We are the ones in power. They can do little to hurt us, but we can do much to either hurt or heal them. We've tried the former option, and it has only increased their hatred. Isn't it time to try something else?