Suddenly some words C.S. Lewis spoke to a British audience in the 1940s seem very current — and very personal.

"Everyone says forgiveness is a lovely idea," Lewis said in a radio address that later became part of his book Mere Christianity, "until they have something to forgive, as we did during the war. And then, to mention the subject at all is to be greeted with howls of anger. It is not that people think this too high and difficult a virtue: it is that they think it hateful and contemptible. ‘That sort of talk makes me sick,’ they say. And half of them already want to ask me, ‘I wonder how you’d feel about forgiving the Gestapo if you were a Pole or a Jew?’

"So do I," Lewis admitted. "I wonder very much."

American Christians today can understand the dilemma very well, perhaps for the first time in our lifetimes. I can understand it especially well. For a few minutes on Sept. 11 — a few minutes that felt like hours — I waited in fear wondering if my sister, who works in Manhattan, was among the dead. I never got past the fear before relief came with the news that she was safe. But the realization that I might’ve gotten different news makes it all too easy to imagine the feelings that would’ve followed. Weeks later, thinking about it still makes me shudder at their intensity, their sheer violence.

To non-Christians the dilemma isn’t apparent; they can simply seek revenge and feel perfectly justified, even righteous, about it. Yet as Lewis went on to say, "I am not telling you what I could do — I can do precious little — I am telling you what Christianity is. I did not invent it. And there, right in the middle of it, I find ‘Forgive us our sins as we forgive those that sin against us’. ... There are no two ways about it. What are we to do? "

What indeed? For several years I couldn’t have answered this question. But Lewis’ explanation of what forgiveness entails — and what it doesn’t — was a great help.

Lewis suggested we begin by forgiving someone easier than the Gestapo (substitute: Osama bin Laden), if only because it’s easier to learn how to handle the tough cases by working on easier ones. But he began his main argument by noting that the command to love our neighbor as yourself raises a revealing question: How exactly do you love yourself?

Do I think well of myself, think myself a nice chap? Well, I am afraid I sometimes do (and those are no doubt my worst moments) but that is not why I love myself. In fact, it is the other way round: My self-love makes me think myself nice, but thinking myself nice is not why I love myself. So loving my enemies does not apparently mean thinking them nice either. That is an enormous relief. For a good many people imagine that forgiving your enemies means making out that they are really not such bad fellows after all, when it is quite plain that they are. Go a step further. In my most clear-sighted moments not only do I not think myself a nice man, but I know that I am a very nasty one. I can look at some of the things I have done with horror and loathing. So apparently I am allowed to loathe and hate some of the things my enemies do.

Lewis confessed that the classic distinction between hating the sin and loving the sinner had long seemed to him "a silly, straw-splitting distinction."

But years later it occurred to me that there was one man to whom I had been doing this all my life — namely myself. However much I might dislike my own cowardice or conceit or greed, I went on loving myself. There had never been the slightest difficulty about it. In fact, the very reason why I hated the things was that I loved the man. Just because I loved myself, I was sorry to find that I was the sort of man who did those things. Consequently, Christianity does not want us to reduce by one atom the hatred we feel for cruelty or treachery. ... But it does want us to hate them in the same way in which we hate things within ourselves: being sorry that the man should have done such things, and hoping, if it is anyway possible, that somehow, sometime, somewhere, he can be cured and made human again.

The real test is this. Suppose one reads a story of filthy atrocities in the paper. Then suppose that something turns up suggesting that the story may be not quite true, or not quite so bad as it was made out. Is one’s first feeling, "Thank God, even they aren’t quite so bad as that," or is it a feeling of disappointment, and even a determination to cling to the first story for the sheer pleasure of thinking your enemies as bad as possible? If it is the second then it is, I am afraid, the first step in a process which, if followed to the end, will make us into devils. You see, one is beginning to wish that black was a little blacker.

There’ve been times when that description fit me. During the Cold War, I’d react impatiently to any suggestion that there might be some virtues or even understandable human motivations among communists: any of them, anywhere. People who made such suggestions I regarded as making excuses for totalitarianism. Sometimes that’s just what they were doing, and make no mistake, I still believe that communism was an immense evil that had to be defeated. (If the corpses of its victims could talk, tens of millions would echo that sentiment.) I don’t repent of anti-communism; I repent of hating my enemies, relishing the emotion, feeling virtuous about it.

We can easily succumb to the same attitude today. Some (by no means all) Americans say they support massive retaliation even if we kill vast numbers of innocent people. We’re hearing slogans like "reduce Afghanistan to rubble" and "bomb them back to the Stone Age." When we let ourselves head down that road we’re not nearly so different from terrorists as we like to believe. We may even get a chilling glimpse in ourselves of the kind of hatred that made them terrorists in the first place; many of them were victims of violence before they became perpetrators of it. But as the cliché goes, two wrongs don’t make a right. We must set a higher standard, for the sake of our own souls.

This isn’t to say we shouldn’t respond militarily against the terrorists themselves. Lewis, for one, was no pacifist: "Does loving your enemy mean not punishing him? No, for loving myself does not mean that I ought not to subject myself to punishment — even to death. If one had committed a murder, the right Christian thing to do would be to give yourself up to the police and be hanged. It is, therefore, in my opinion, perfectly right for a Christian judge to sentence a man to death or a Christian soldier to kill an enemy." Scripture repeatedly makes the same point, stating that government bears the sword for good reasons: to fight injustice, to punish evildoers.

"I imagine," Lewis wrote, "somebody will say, ‘Well if one is allowed to condemn the enemy’s acts, and punish him, and kill him, what difference is left between Christian morality and the ordinary view?’ All the difference in the world."

Remember, we Christians think man lives forever. Therefore, what really matters is those little marks or twists on the central, inside part of the soul which are going to turn it, in the long run, into a heavenly or hellish creature. We may kill if necessary but we must not hate and enjoy hating. We may punish if necessary, but we must not enjoy it. In other words something inside us, the feeling of resentment, the feeling that wants to get one’s own back, must simply be killed.

We, of course, can only do so much about our feelings. But we can remind ourselves of who we really are, as Paul did when (speaking in the present tense, not the past) he proclaimed himself "chief of sinners." We can remind ourselves of Jesus’ authoritative declaration that hate is, spiritually speaking, the same as murder. And with that in mind, we can give thanks once again that God forgives us so completely through Christ that when He see us, He sees the sinless Christ in our stead.

Osama bin Laden can’t say that. But we can pray that the day comes when he can; in fact, Christ commands us to do so. And we can keep praying right up to the last day of bin Laden’s life — even if our government, for the sake of justice in this world, must take action to end it.