The Concept of a “Just War”

Adapted from ICEJ President Dr. Juergen Buehler’s presentation at the ICEJ’s recent International Leadership Conference (ILC) in Helsinki.

Most churches today struggle with the concept of a just war. Most Western countries have not had wars in recent decades; thus, we have developed a pacifist attitude toward any war situation. But how should Christians approach war? This question is especially relevant considering Israel’s current conflict with Hamas.

Theology around Pacifism

Our friend Prof. Gerald McDermott recently stated at the ICEJ Envision conference that “pacifism is the immoral privilege reserved for those who sit safely at home.” In a way, our theology around pacifism developed in countries that were living in peace over the last seven to eight decades. But if you go back in church history, probably the most profound voice on this topic was Thomas Aquinas in the thirteenth century. He defined the idea of a “just war” as having three requirements.

First, declaring war is not the business of a private person; it needs proper authority. Back then, you had little fiefdoms that were constantly at war. Aquinas also said that you need a proper political structure to declare war.

Second, a just war requires the need to right a grievous wrong. Someone has been an aggressor and deserves to be held to account. A just war seeks to correct a nation for refusing to make amends for wrongs it has inflicted or restore what another nation has unjustly seized. This certainly applies to Gaza—Hamas brutally attacked Israel, took hostages, and broke many moral standards.

Third, the authority seeking to right the wrong must have upright intentions to advance a moral code or remedy an injustice. We should reject wars waged for motives of aggrandizement or cruelty and accept those undertaken to punish evil, secure peace, and uplift the common good. That is exactly what Israel is doing.

Israel is being accused of committing genocide in Gaza. Yet the Israeli army is probably the most moral, humane army in history. They are going far above and beyond any normal measures to ensure there are a minimum of civilian casualties.

At the same time, if you look at Hamas and read through the Geneva Conventions on warfare, Hamas has broken every single rule in the book, every principle of warfare. They are using their own people as human shields, not protecting them but rather exposing them to harm. Misusing humanitarian institutions, like hospitals and schools. Torturing and raping people and vandalizing property, all of which can be seen in the videos from October 7. It is scandalous, and yet the international community is not holding Hamas accountable.

Is the Idea of a “Just War” in the Bible?

So what does the Bible actually say about war? In a way, the most powerful passage about war is in the “Song of Moses” in Exodus 15:3: “The Lord is a man of war,” a statement that contradicts many of our religious assumptions about God as a peacemaker. Yet the Bible clearly states He is a man of war. And in context, it is speaking of a real battle fought with real weapons, with real men being killed. God actually was fighting to annihilate an entire enemy army.

Psalm 24 also says that “the Lord is mighty in battle.” This psalm of David is about a very real war experience.

Then the Bible gives us the names of the Lord, and the most common is Adonai Tzva’ot, meaning the “Lord of Hosts” or armies. The Lord is called this 232 times in the Bible. Some might say this is all Old Testament. Yet the same word is used at least two or three times in the New Testament. And remember, in Hebrews 13:8, the Bible says Jesus Christ is the same yesterday, today, and forevermore. God always remains the same.

If you still think this is all Old Testament, read Revelation 19:11:

Now I saw heaven opened, and behold, a white horse. And He who sat on him was called Faithful and True, and in righteousness He judges and makes war.

In addition, the apostle Paul teaches in Romans 13:1–7 that earthly governments carry the sword as “God’s minister, an avenger to execute wrath on him who practices evil.” Thus, the New Testament does not shy away from governments using military force in a just war but instead supports it.

Israel’s Reality Today

Of course, as believers, we are not called to engage in physical battles because the church does not have a nation with an army. But it is a different reality for the restored nation of Israel. Israel has no choice but to defend itself against evil aggression.

—By ICEJ President Dr. Juergen Buehler