You Shall Not Kill - Can a Christian Go to War?

In Poland, where I live, the question of military service was theoretical for most of us until a few years ago. Today it is not. A war is being fought across our eastern border, Polish politicians talk about universal military training and a return of conscription, and young men have started asking themselves what they would do if the call-up letter arrived. (Poland borders Ukraine, Belarus and Russia’s Kaliningrad region, and compulsory service was suspended here in 2009.) For a Christian this is not only a matter of fear or convenience. It is a matter of conscience: am I allowed to kill?

I won’t pretend that the Bible answers this with a single verse. For two thousand years Christians have reached different conclusions, and some of them are people of deep faith. But my thesis is clear: a disciple of Jesus is called to a path without killing - and can serve their neighbors, even in wartime, without a weapon in hand. I will show what I base it on and fairly present what stands most strongly against it.

Let’s Start with Honesty: What “You Shall Not Kill” Actually Means

You shall not murder.

- Ex 20:13 (ESV)

Many English Bibles say “You shall not kill.” The ESV, as you can see, says “murder,” and that matters. The Hebrew word ratsach refers mainly to unlawful killing: murder, sometimes accidental killing. The same Law of Moses prescribes capital punishment for certain crimes, knows the wars of Israel, and even sets up cities of refuge for those who killed unintentionally. The commandment, read in isolation, does not settle the question of war.

This caveat is important, because many pacifists build their position on that one sentence alone, and then it is easy to knock down. So I go further, to how Jesus reads that commandment.

Jesus Doesn’t Abolish the Commandment - He Deepens It

You have heard that it was said to those of old, “You shall not murder; and whoever murders will be liable to judgment.” But I say to you that everyone who is angry with his brother will be liable to judgment.

- Mt 5:21-22 (ESV)

Jesus is not satisfied with the letter. The commandment no longer concerns only the act, but the heart: the roots of hatred, contempt, the desire for revenge. If even anger is liable to judgment, it is hard to believe that His disciple can calmly reach for a weapon against another human being.

In the same sermon He goes further:

But I say to you, Love your enemies and pray for those who persecute you.

- Mt 5:44 (ESV)

The enemy is the recipient of love here, not a target. War by definition requires the opposite: seeing the person on the other side as an enemy to be neutralized. Remember also Jesus in the Garden of Gethsemane when Peter drew his sword:

Then Jesus said to him, “Put your sword back into its place. For all who take the sword will perish by the sword.”

- Mt 26:52 (ESV)

Peter had a just cause: he was defending an innocent man, the Son of God Himself. And yet he heard “put your sword back.” This passage does not settle everything (it was a unique moment tied to the cross), but it shows that even a righteous cause does not automatically open the way to violence for a disciple.

”My Kingdom Is Not of This World”

Jesus answered, “My kingdom is not of this world. If my kingdom were of this world, my servants would have been fighting, that I might not be delivered over to the Jews. But my kingdom is not from the world.”

- Jn 18:36 (ESV)

These are Jesus’ words to Pilate, and I think they are rarely quoted in this debate. Jesus says plainly that His servants do not fight because of the nature of His kingdom. The kingdoms of this world defend themselves with the sword because they depend on it. The kingdom of God has other means: truth, love, witness, and in the end the cross.

Paul develops the same idea in Romans:

Do not be overcome by evil, but overcome evil with good.

- Rom 12:21 (ESV)

A Christian’s victory over evil does not consist in defeating an opponent, but in not letting evil turn them into someone like it.

The Early Church: A Witness That Surprises Many

To be fair, historians debate what military service looked like for Christians before the fourth century. There were Christians in the army, and not every Church Father spoke with one voice. But several important testimonies point clearly in one direction:

Tertullian (around AD 200) wrote that a Christian should not serve in the legions, because in disarming Peter Christ disarmed every soldier.
Hippolytus, in the Apostolic Tradition (3rd century), forbade admitting to the church those who wanted to remain soldiers and kill.
Origen answered a pagan critic that Christians do not fight in the emperor’s army, but pray for him and in that way serve him.
Maximilian of Tebessa (AD 295) was executed for refusing conscription because he was a Christian.
According to his biographer, Martin of Tours (4th century) said: “I am a soldier of Christ; I am not allowed to fight.”

The turning point came after Constantine, when the church began to have the state as an ally. Augustine then formulated the doctrine of the just war, which Thomas Aquinas later developed. It is a serious tradition and worth knowing. But it is also worth noting that the earlier tradition is at least as old as it, and in some respects older. During the Reformation the Anabaptists returned to the position of non-violence, and their Schleitheim Confession (1527) explicitly rejects the sword as a tool of Christ’s disciple.

The Strongest Counterargument

I don’t want to fight it behind closed doors. It goes like this:

Romans 13:4 says that the authority “does not bear the sword in vain,” and Luke 3:14 and Acts 10 show soldiers whom no one told to leave their profession. Besides, if someone attacks your family and you do nothing, aren’t you leaving them to their fate? Is that love of neighbor?

These are not weak arguments. Let me try to answer honestly.

Romans 13 speaks about the role of the state: the authority bears the sword, not the disciple of Jesus. Paul describes an institution whose work God permits, but in the same chapter he speaks of love, which “does no wrong to a neighbor” (Rom 13:10). The conclusion that a Christian may become the one who wields that sword does not follow directly from the text.

The soldiers in Luke and Acts: John the Baptist tells them not to extort and not to harm. Cornelius receives the Holy Spirit. But Scripture says neither that they stayed in the army nor that they left it. An argument from silence works both ways and cannot be the foundation of either position.

Defending loved ones. This is genuinely hard. I’m not claiming the answer is easy or that I don’t feel the tension myself. But a pacifist is not a passive bystander. Proverbs 24:11 commands us to rescue those who are being taken away to death. Not killing is not the same as doing nothing. One can protect, rescue, evacuate, treat wounds, stand in between, bear witness and suffer for others, and still not kill. Christianity has known such a stance from the beginning: going to the sick during an epidemic, ransoming captives, hiding the persecuted. That is also defense, just with a different weapon.

Why I Believe the Path of Peace Is More Biblical

Since I have presented the strongest counterargument, let me also say plainly how I weigh the two sides. I believe the path of peace is more faithful to Scripture than the doctrine of the just war, and here is why:

The New Testament contains not a single command for the church to fight with the sword. The fight it speaks of is spiritual: “we do not wrestle against flesh and blood” (Eph 6:12), and “the weapons of our warfare are not of the flesh” (2 Cor 10:4). Where Scripture speaks of the disciple’s armor, it speaks of truth, righteousness, peace and prayer.
The just war doctrine does not come from the Bible, but from later theological reflection. It was formulated in the fourth and fifth centuries by Ambrose and Augustine, drawing partly on Roman philosophical tradition (Cicero among others), and developed by Thomas Aquinas. It is a serious and noble attempt to reconcile the Gospel with the duties of the state, but it is a human construction that arose after the church’s situation changed, not the teaching of Jesus or the apostles.
The criteria of a just war themselves show how hard they are to meet. Almost every side in every war believes its cause is just, and Christians on both sides of the front have prayed to the same God for victory. If the criteria settle nothing in practice, it is hard to treat them as a firm foundation for a disciple’s conscience.
The cross is the pattern of victory. Christ did not defeat evil by killing His enemies, but by giving His life for them. The apostles call us to follow in His steps (1 Pet 2:21).

I call this my own assessment, not a dogma. Augustine and Aquinas appealed to Scripture (Rom 13, Luke 3:14), and I respect Christians who reach different conclusions on that basis. But if you ask which path I consider closer to the words and example of Jesus, my answer is: the path of peace.

What This Means in Practice: Service Without Killing

Rejecting killing does not mean rejecting responsibility for others. Quite the opposite. In wartime and in times of danger there are many roles in which one can serve without a weapon:

medic and rescue worker,
civil defense, evacuation, rescue operations,
logistics and humanitarian aid,
chaplain and spiritual support,
helping refugees and the families of victims.

The best-known example is Desmond Doss, a Seventh-day Adventist who served as a medic in World War II and refused to carry a weapon. On Okinawa in 1945, according to accounts, he carried about seventy wounded men out of the line of fire and received the Medal of Honor. He killed no one, and he saved many.

One warning: conscientious objection makes sense only if it is genuine. You must not pretend to convictions for the sake of convenience. A Christian who lies to avoid service breaks something more important than conscription rules. Your conscience has to be examined honestly first, in the light of Scripture, within a community, in prayer.

The Cost and the Fear

The path without the sword is not comfortable. It can cost you your job, rejection, legal penalties, and in extreme circumstances more. That is why it must be considered soberly.

But we also must not let fear decide for us. Jesus says: “Do not fear those who kill the body but cannot kill the soul” (Mt 10:28). That doesn’t mean fear is a sin, but that fear does not get the last word. Jesus foretold that wars and rumors of wars would continue until the end (Mt 24:6), but added: “See that you are not alarmed.” I wrote about how to look at such signs of the times in when will Christ return.

Ultimately the question is not: “what can I do so that nothing happens to me?” It is: “how can I faithfully follow Jesus in a world that goes another way?” And that question has no safe version.

Summary

The commandment “you shall not kill” does not by itself settle the question of war, but Jesus deepens it and teaches us to love our enemies.
His kingdom “is not of this world,” so it does not defend itself with the sword.
The oldest tradition of the church saw this as the disciple’s path, while the later doctrine of the just war is a human theological construction, not directly the teaching of Scripture. That is why I consider the path of peace more faithful to the Bible.
Rejecting killing does not mean watching evil passively. There are many ways to protect others without a weapon.
Every person’s conclusion must come from their own honest discernment, not from pressure or convenience.

If you are wrestling with this question in the context of forgiveness and loving your enemies, I also recommend the text on forgiveness as the hardest commandment, and if you want to understand why the Old Testament knows wars while the New speaks of loving enemies, read why was God cruel in the Old Testament.