Just War: When Is War Justified?

Hey friends,

War is one of those topics that makes us pause. It’s uncomfortable, weighty, and deeply consequential. As Christians, we long for peace—but we also live in a fallen world where evil must sometimes be confronted. So how do we reconcile our call to be peacemakers with the reality that, at times, war is necessary?

That’s where the doctrine of just war comes in. Rooted in Scripture and articulated by Augustine, it helps us discern when war is justified and how it must be conducted in a way that honors God. And when we consider it through the lens of general equity theonomy, we see that God’s moral law provides the foundation for justice—even in matters of war and peace.

So, settle in, take a deep breath, and let’s walk through this together. What does the Bible say about war? When is it righteous? And how do we, as Christians, think rightly about it?

Is There a Time for War?

As much as we long for peace, Scripture acknowledges that war is sometimes necessary in a fallen world. Ecclesiastes 3:8 tells us there is “a time for war, and a time for peace.” While war should never be waged recklessly, the Bible does not condemn all warfare outright. Instead, it provides guidelines for when war is just and necessary.

• God Himself wages war – The Old Testament is filled with examples of God leading Israel into battle against wicked nations (Exodus 15:3, Joshua 6, 1 Samuel 15:3). God’s justice sometimes requires war to bring judgment.

• Governing authorities bear the sword – Romans 13:4 teaches that civil rulers are God’s servants, “an avenger who carries out God’s wrath on the wrongdoer.” While this applies to maintaining justice within a nation, it also extends to the defense of nations against aggression.

• Defending the innocent is righteous – Proverbs 24:11 commands, “Rescue those who are being taken away to death; hold back those who are stumbling to the slaughter.” Failing to intervene against violent oppression is not righteousness—it is cowardice.

These principles form the biblical foundation for the idea of just war, which was first systematized by Augustine.

Augustine and the Just War Tradition

In the early church, many Christians wrestled with whether war could ever be justified. Augustine (354–430 AD) was one of the first to articulate a clear framework for just war. He argued that while war is always tragic, it can sometimes be necessary to restrain evil and promote justice.

Augustine laid out key principles for what makes a war just:

1. Just Cause – War must be fought for a legitimate reason, such as self-defense or protecting the innocent. It cannot be for conquest, revenge, or personal gain.

2. Right Authority – Only lawful governing authorities may declare war (Romans 13:1-4). Private individuals or groups cannot wage war on their own.

3. Right Intention – The goal of war should be justice and peace, not cruelty, revenge, or destruction.

4. Proportionality – The force used in war must be appropriate to the cause. Excessive violence is unjust.

5. Last Resort – War should only be waged after all peaceful means have been exhausted.

These principles shaped Western thought on warfare for centuries and remain relevant today. Augustine’s framework aligns with biblical justice—especially when viewed through the lens of general equity theonomy.

General Equity Theonomy: A Biblical Framework for Justice

General equity theonomy holds that God’s law remains morally binding today, not in the form of Israel’s old covenant civil laws, but in its enduring principles of justice. This applies not just to personal ethics but also to civil governance—including warfare.

1. God’s Law Establishes Justice – Civil rulers are required to uphold righteousness according to God’s law (Psalm 2:10-12, Deuteronomy 16:18-20). This means that war, when necessary, must be conducted in a way that reflects divine justice.

2. Self-Defense and Protection Are Biblical – The Sixth Commandment forbids murder (Exodus 20:13), but it does not prohibit just killing in defense of the innocent. Exodus 22:2 affirms the right to use force to protect life. The same principle extends to national defense.

3. War Must Be Just, Not Tyrannical – Deuteronomy 20 provides principles for warfare, including offering peace before war (v. 10) and forbidding wanton destruction (v. 19). General equity means these principles still guide nations today.

4. Unchecked Evil Must Be Confronted – A government that refuses to punish wickedness is itself complicit in evil (Proverbs 25:5, Romans 13:4). In the face of unjust aggression, the failure to act is not righteousness but negligence.

General equity theonomy teaches that war is not inherently sinful—it is the unjust shedding of blood that is condemned. Righteous warfare must be conducted under God’s moral order, with the aim of establishing justice and peace.

When War Becomes Unjust

Not all wars are just. Augustine’s framework, combined with biblical principles, shows us what makes a war unjust:

1. War for Greed or Power – When war is waged for personal gain, expansion, or imperialism, it is unjust (James 4:1-2).

2. Disregard for Human Life – Even in war, human life bears God’s image (Genesis 9:6). Indiscriminate killing, targeting civilians, and excessive brutality are evil.

3. Ignoring Just War Principles – A war that bypasses lawful authority, is waged with evil intent, or ignores proportionality becomes unjust.

A nation must carefully weigh whether its cause is truly just before engaging in warfare. Failure to do so brings God’s judgment upon a nation (Habakkuk 2:12).

How Should Christians Respond?

In a world filled with conflict, how should we, as followers of Christ, think and act?

1. Pray for Peace – Even when war is necessary, we should never rejoice in bloodshed. Pray for peace and wisdom for leaders (1 Timothy 2:1-2).

2. Support Just Rulers – As Romans 13 teaches, civil authorities are ordained by God to uphold justice. We should support leaders who govern righteously and oppose those who lead nations into unjust wars.

3. Trust in God’s Sovereignty – The ultimate battle belongs to the Lord (Psalm 46:9). Whether in times of war or peace, our hope is in Christ, the Prince of Peace, who will one day establish perfect justice.

   
   

Final Thought: A Time for War, A Time for Peace

War is never to be taken lightly. But in a fallen world, it is sometimes necessary to uphold righteousness and restrain evil. As Christians, we must think biblically about warfare, following the principles of just war and applying the enduring moral order of God’s law through general equity theonomy.

One day, war will cease. Christ will return, and swords will be beaten into plowshares (Isaiah 2:4). But until that day, we must seek justice, love mercy, and walk humbly with our God (Micah 6:8)—even in times of war.

Soli Deo Gloria—to God alone be the glory!