Yesterday, Robert Jeffress, an evangelical pastor and close adviser to Donald J. Trump, said that the president has biblical permission and moral authority to “take out” North Korean supreme leader Kim Jong Un. Citing Romans 13, Rev. Jeffress said that God grants governments the authority to punish evildoers with whatever means necessary.

Thomas Merton was no stranger to the horrors of war.

Rev. Jeffress has added to the tensions prompted by the recent saber-rattling between U.S. and North Korean military forces. A bracing contrast to his take on Scripture can be found in the works of Thomas Merton, an American writer, mystic and Trappist monk who used apocalyptic language to demonstrate how Christians must avoid war—and any kind of religious justification for war—altogether.

Merton (1915-68) was no stranger to the horrors of war. Born at the beginning of World War I in a French town where “the world was a picture of hell,” Merton described his childhood in this way: “Not many hundreds of miles from the house where I was born, they were picking up the men who rotted in the rainy ditches among the dead horses in a forest of trees without branches along the river Marne.”

As a monk at the Trappist Abbey of Gethsemani in Kentucky, Merton wrote many books that would shape Christian thought throughout the 20th century. A persistent theme in his writings is the call for Christians to recognize their vocation as peacemakers. After living through two world wars, Merton was horrified by nuclear threats at the height of the Cold War. In an essay originally published in 1962, he writes:

There is no need to insist that in a world where another Hitler is very possible the mere existence of nuclear weapons constitutes the most tragic and serious problem that the human race has ever had to contend with. Indeed, the atmosphere of hatred, suspicion and tension in which we all live is precisely what is needed to produce Hitlers.

His horror at the mere existence of nuclear arms brought Merton to reflect on Christ’s promise of peace. Christ, the Prince of Peace, does not simply offer a kind of supernatural peace, Merton writes. Rather, he compels those who follow him to actively strive for peace in this life:

Christ Our Lord did not come to bring peace to the world as a kind of spiritual tranquilizer. He brought to His disciples a vocation and a task, to struggle in the world of violence to establish His peace not only in their own hearts but in society itself.

This is Merton’s principal point: Christians may not excuse themselves from the work of building peace in the world. It is the vocation Christ gives us in baptism. Amid North Korean nuclear missile tests and American promises of “fire and fury,” calls for peace may sound naïve. Yet Merton reminds Christians of the responsibility that comes with our baptism. As the world commemorates and mourns the 72nd anniversary of the bombings of Hiroshima and Nagasaki, Merton’s critique of Christian failure to recognize this vocation is especially poignant:

There can be no doubt that Hiroshima and Nagasaki were, though not fully deliberate crimes, nevertheless crimes. And who was responsible? No one. Or “history.” We cannot go on playing with nuclear fire and shrugging off the results as “history.” We are the ones concerned. We are the ones responsible. History does not make us, we make it—or end it.

Given this responsibility, Merton advises Christians on how they can live the vocation of peace in the world of nuclear threats. In a letter penned to his friend Etta Gullick in the 1960s, Merton writes:

I do not mean to say that you have to swim out to nuclear submarines carrying a banner, but it is absolutely necessary to take a serious and articulate stand on the question of nuclear war…. The passivity, the apparent indifference, the incoherence of so many Christians on this issue, and worse still, the active belligerency of some religious spokesmen, especially in this country, is rapidly becoming one of the most frightful scandals in the history of Christendom.

Merton believed that Christians had a simple choice with regard to the scandal of violence in Christian history: Do we continue (actively or passively) betraying our vocation as peacemakers or do we make a stand for an end to violence? In Seeds of Destruction (1980), he writes:

What are we, the dwindling and confused Christian minority in the West, going to do? Or at least, what do we really want to do? Do we intend to settle our problems peacefully or by force? Have we anything left to say about it at all? Have not the decisions been taken, to a great extent, out of our hands? Not yet. Among our leaders, some are Christians…. These leaders will (we hope) take kindly to suggestions and to pleas that are based on Christian ethical norms.

If Merton was alive today, I suspect he would not be surprised by the words of Pastor Jeffress, but his response would be sharp and challenging to us all.

Angelo Jesus Canta is a graduate student of theology at the Boston College School of Theology and Ministry and former O’Hare Fellow at America. He studied Marian devotion in Italy and China as a Ricci Scholar at Loyola University Chicago.