Editor’s Note: The following address was delivered at Morning Prayers at Harvard University on September 20, 2010.

Exactly nine years ago today, on the steps of Harvard’s Widener Library, I took part in a peace vigil to honor those who had lost their lives in the terrorist attacks on September 11, 2001. We were all terrified back then—still reeling from the carnage, still grieving for our collective loss, all of us overcome with anxiety and anger.

For me, it was the anger that caused the worst anxiety—the understandably human and yet still inhumane call for violent retaliation that only increased in the days, months, and years after 9/11. Resisting that impulse to vengeance—the need to have someone, anyone, “pay” for what happened that day—was what I had in mind nine years ago when I said that “I deplore those who would deploy rhetoric and deploy troops” before they stop to think about the consequences of their words and actions. As some of you know, my words and subsequent actions—on behalf of peace rather than war—got me into some trouble. Lynne Cheney accused me of being “short on patriotism” and Rush Limbaugh suggested I should be deported. I received hate mail and death threats. I was pilloried in the press and caricatured by critics, among them my students, classmates, and colleagues. I’ll never forget those days.

As a Christian, I have always taken very seriously Jesus’ exhortation in the Sermon on the Mount from the Gospel according to Matthew: “You have heard that it was said, ‘An eye for an eye, and a tooth for a tooth.’ But I tell you, do not resist an evildoer. But if anyone strikes you on the right cheek, turn the other also.”

These teachings—versions of which exist in every faith tradition—have fallen on deaf ears in our troubled times. Instead of peaceful alternatives, we find ourselves perpetually at war. Rather than search for faith in one another, we live in fear of one another. To varying degrees, we are all to blame—whether we rushed to support military intervention in Afghanistan and Iraq or were too late in opposing it; whether we blindly support our troops as they fight and kill or blithely go about our lives as we enjoy the privilege of not having to do this dirty work ourselves; whether we were silenced by the intensity of our so-called “patriotism” or remain skeptical about the impact of our protests. Indeed, the most striking American tragedy in these last nine years—far worse than the tragedy of 9/11 itself—is just how weak we have been in the wake of war.

And this tragedy, I fear, has only gotten worse. We saw it in the military failures of a Republican president, and we are seeing it again in the moral failings of his Democratic successor. We see it not only in the nihilist violence of Muslim extremists but also in the anti-Muslim vitriol of a Christian pastor from Florida and a Jewish publisher of The New Republic. We compound it every time we allow our private suspicions and public silences to confound the better angels of our nature.

Yet I haven’t lost hope. Over the summer, I attended Seeds of Peace, a summer camp in Maine for young people committed to bringing about a more peaceful and loving world. These courageous teenagers come from all over the world—Israel and Palestine, Jordan and Turkey, Iraq and Iran, Pakistan and Afghanistan, Europe and the United States—to work through otherwise ancient and intractable differences to build common ground. I needn’t underscore the difficulty of this work; we are all shaped by powerful doctrines—religious, nationalist, and otherwise—that insist upon a world of oppositions, where the “other” is so often the “enemy.” For many of the young women and men at Seeds of Peace, this was their first trip outside of the places they call “home,” the first chance they’ve ever had to see the “enemy” as “friend,” the “other” as “sister” and “brother.” I found myself in awe of these young “seeds of peace,” perhaps most of all because they have found the courage to imagine a radically different world from the one we adults have forced upon them.

During a morning discussion of the history of non-violent social movements, I was stopped in my tracks by a question from a young man, barely 15 years old, from Afghanistan. “But what am I supposed to do?” Ahmad asked. “My country only knows violence; it trains boys like me to be violent. What do I say to my friends and relatives when they hand me a gun?” I had been talking about histories, and theories, of non-violence. But his was a personal concern, as practical as it was profound: in a world full of violence, shaped by a war in which both of us—an Afghan and an American—are deeply implicated, how could he be expected to choose peace? Put another way, how can we expect him to be any different than the rest of us?

I paused for a very long time, and then said: “Don’t pick up the gun.”

Ahmad was as surprised as I was by my blunt suggestion—one that points the way to a world we seem unable to imagine and unwilling to create (and I’m not sure which is worse). After a time, his eyes brightened. He nodded and said, “OK, I will try.” Seed of peace indeed.

My prayer this morning is this: that we somehow find it in ourselves to not pick up the gun. And may we also find the moral courage to put down the guns we have already picked up, to abolish the weapons of mass destruction in our own countries before we expect the same of others, to dismantle the doctrines that divide us, to break the vicious cycle of fear and violence that threatens us, to turn the other cheek, and to demand an end to war—once and for all.

For Ahmad’s sake, and for the sake of every last human soul on this planet, let us, finally, be the peacemakers. For only they are blessed.