July 27, 2026
If war is ever lawful,
then peace is sometimes sinful.
—C. S. Lewis
War. It’s sometimes romanticized. It’s usually defended and even glorified. It’s often underestimated and regretted.
But is war ever justified? Not: do powerful people try to justify it? (We know the answer.) But was there ever a physical war waged for truly just reasons and through just actions?
Those Christians who believe that war can be justified often appeal to Romans 13:4 (among other passages):
“For the one in authority is God’s servant for your good. But if you do wrong, be afraid, for rulers do not bear the sword for no reason. They are God’s servants, agents of wrath to bring punishment on the wrongdoer.” (Romans 13:4, NIV)
And if the government which bears the sword (presumably in war among other uses of force) does so as God’s servant, then it would seem that Christians of conscience could also participate in the military without feeling they are disobeying God.
Yet, from the earliest times, there have been a significant number of Christian leaders who embrace a non-violence posture, stating that, while secular governments will do what they have always done, a follower of Jesus should never go to war, along the lines of Matthew 5:38-40 (and other passages):
“You have heard that it was said, ‘Eye for eye, and tooth for tooth.’ But I tell you, do not resist an evil person. If anyone slaps you on the right cheek, turn to them the other cheek also. And if anyone wants to sue you and take your shirt, hand over your coat as well.” (Matthew 5:38-40, NIV)
“War. It’s sometimes romanticized. It’s usually defended and even glorified. It’s often underestimated and regretted. But is war ever justified?”
Of the positions, the first is often referred to as “Just War Tradition,” while the second is often called “Pacifism” (whose advocates have sometimes been delineated into “non-violence” pacifists who refuse to participate in military violence and “non-participation” pacifists who refuse to participate in any military endeavor whatsoever, even in noncombatant ways.)
This article is not written to take a stand between these positions—there are leaders in the RENEW.org Network who hold either position. While I want to acknowledge them both, I want to focus on the mindset of those who believe in Just War Theory. This is because Just War advocates find themselves in more of a “messy middle,” where important principles can get lost amid the chaos of war and the urgency to win whatever the cost. Just War advocates aren’t opting for the less complicated views on either side—neither an advocacy which says, “Our country, right or wrong!” nor a blanket refusal to participate in any war. If you’re a Christian who has stepped into the messy middle where you believe war can be justified, you obligate yourself to think biblically about what might constitute a just war.
Honestly, many just uncritically accept whatever one’s media says about war, for or against—without reflecting on the ways Jesus would want us to think about war. As I’m writing this, that would include what’s happening in Iran, in Israel, and in the Ukraine, but this is a problem that’s been with us throughout Christian history. With our nation currently engaged—explicitly and implicitly—in three wars, it’s a miss when we give the people we lead no guidance, whether in sermons, classes, or discussions, on biblical principles that should guide us, restrain us, or even cause us to question when our country is acting justly or unjustly.
“Many just uncritically accept whatever one’s media says about war, for or against.”
Again, many of the earliest Christians were pacifists, but the influential Christian leader Augustine began to formulate a Just War tradition which has influenced the church ever since. In a letter written around A.D. 412, Augustine noted, “If Christian teaching condemned all warfare, then the soldiers in the gospel who were seeking guidance about their security would have been told to throw away their weapons and withdraw entirely from the army.”
This is a reference to the soldiers who, when they asked John the Baptist what repentance would look like for them, were told to be content with their wages and to not use their force for selfish gain—but they were never told to stop being soldiers. Another example: the Roman centurion Cornelius was baptized into Christ and then apparently became a Christian centurion in Caesar’s army. Augustine advocated for Christians in the military—but also became very influential in how a Christian should approach war. He stressed that warfare is legitimate if and only if it is waged for the sake of peace and in a moral way.
The Just War doctrine has been developed over the centuries, especially by Thomas Aquinas—to build on Augustine’s contention. Put simply, a just war is warfare that is justified by legal and moral reasons.
“A just war is warfare that is justified by legal and moral reasons.”
In particular, Just War theory deals with two fundamental questions concerning the ethics of war and peace: 1) When is it morally and legally justified to go to war? 2) What moral principles should we follow during war? There are three key terms often used:
- Jus ad bellum– When is it morally justified to go to war (to start a war)?
- Jus in bello– What constitutes moral conduct during war (how to fight fairly)?
- Jus post bellum – What are just goals and conduct after war (fair rules after a war ends)?
Are you someone who in principle can advocate war—but only when it’s done in a principled, just way? Then here’s a reminder of what justice would look like in wartime: 
Just Reason for War (Jus ad Bellum)
- Just Cause: Only to defend innocent life from serious aggression.
- Last Resort: Make sure all diplomatic means have been tried before applying force.
- Proper Authority: Only a legitimate government or authority can declare war.
- Right Intention: Seek only to restore peace and justice, not gain land or power.
- Chance of Success: Avoid fighting a war you will likely lose and that will cause needless deaths.
- Proportionality: The overall good to be gained by fighting must be greater than the horribleness of war.
Just Behavior in War (Jus in Bello)
- Discrimination: Combatants must distinguish between soldiers and civilians. Civilians should never be targeted intentionally (e.g., using chemical weapons on a population).
- Proportionality: Use no more force than is needed to achieve a military objective. Do not be wantonly violent.
- Treatment of Captives: Abide by prisoner of war rules.
Just Intentions after War (Jus Post Bellum)
- Just Peace: Don’t insist on punitive terms. Seek reconciliation and fair peace.
- Reconstruction: Help restore the defeated country and punish the political leaders if responsible for crimes of war.
Again, if you believe war can be justified within a Christian perspective, become familiar with the Just War doctrine. So, for example, as I’m writing this, I am actively asking: Is the USA war against Iran just, according to these principles? What about the war between Russia and Ukraine? How about what the Israelis have done and are doing in Gaza and Lebanon, especially in response to October 7?
I’m not suggesting there are easy answers here (this is the messy middle, after all). But hard-fought answers are much more becoming to Christians than an easy militarism that makes one’s own country the moral center.
“Hard-fought answers are much more becoming to Christians than an easy militarism that makes one’s own country the moral center.”
There are numerous books and articles available to pursue more information along these lines. One book I have found helpful is by J. Daryl Charles and Timothy J. Demy, called War, Peace, and Christianity: Questions and Answers From a Just-War Perspective.
It is easy to get caught up into the narratives provided by the surrounding culture, but Christians must resist that temptation. In this and every other ethical issue, we follow the guidance of the apostle Paul in 2 Corinthians 10:5 (NIV):
“We demolish arguments and every pretension that sets itself up against the knowledge of God, and we take captive every thought to make it obedient to Christ.”
