This post is part of the “Murder vs Killing: What the Bible Actually Says” series. If you haven’t read Part 1: Justice & Mercy in the Law, you may want to start there.
In Part 1, we examined justice and mercy in God’s law. Now we turn to one of the hardest areas: war. How does Scripture handle violence in battle, and what does that mean for us today?
War in the Old Testament
The most troubling passages of Scripture often involve war. God commands Israel to annihilate the Amalekites (1 Samuel 15:3), destroy the inhabitants of Canaan (Deuteronomy 7:1–2; 20:16–18), and wage holy war under Joshua. Psalm 137:9 even voices the horror of exile with words of violent revenge.
Atheist critics such as Richard Dawkins and Charles Templeton have labeled the Old Testament God “vindictive” and “bloodthirsty.” These objections highlight the difficulty of the biblical war passages, but the text itself provides context. The wars of Israel were not arbitrary campaigns of conquest, but acts of divine judgment against nations steeped in idolatry, child sacrifice, and sexual corruption. God waited centuries before judging the Canaanites (Genesis 15:16), showing patience and offering time to repent. Even in judgment, mercy was possible: Rahab and the Gibeonites are clear examples of those who turned to Him and were spared.
Scholars like Paul Copan (“Is God a moral monster“) and John Dickson (“A Doubter’s Guide to the Bible“) argue that the language of “utter destruction” may reflect the hyperbole of ancient warfare, focused on military strongholds rather than literal extermination. Regardless, the biblical authors saw these wars not as genocide but as divine judgment.
War in the New Testament
The New Testament shifts the discussion of war in a striking way. Jesus does not call His followers to advance His kingdom by force. Instead, He teaches personal non-retaliation: “If anyone slaps you on the right cheek, turn to him the other also” (Matthew 5:39). He commands His disciples to love their enemies and pray for those who persecute them (Matthew 5:44). When Peter drew his sword at the arrest of Jesus, cutting off the servant’s ear, Jesus rebuked him: “Put your sword back into its place. For all who take the sword will perish by the sword” (Matthew 26:52).
At the same time, the New Testament recognizes the ongoing role of governments. Paul teaches that rulers “do not bear the sword in vain” but are “the servant of God, an avenger who carries out God’s wrath on the wrongdoer” (Romans 13:4). The picture is clear: individual disciples of Christ are forbidden from vengeance, but the state, as God’s servant, still carries the responsibility to restrain evil.
Early Christian thinkers struggled to hold these truths together. Augustine of Hippo (354–430) was among the first to argue that war could sometimes be morally justified. For Augustine, a war may be just if it is declared by a legitimate authority, fought for a just cause, and waged with the right intent; not for conquest or revenge, but for the protection of the innocent and the restoration of peace.
Several centuries later, Thomas Aquinas (1225–1274) systematized Augustine’s thoughts into what became known as Just War theory. Aquinas added criteria such as proportionality (the response must not exceed the harm done) and last resort (every peaceful option must be exhausted first). This framework deeply influenced Christian reflection on war in the Western tradition.
Not all Christians agreed. In the 16th century, the Anabaptists emerged as part of the Radical Reformation. They rejected the idea that war could ever be justified for followers of Christ. Taking the Sermon on the Mount literally, they refused military service, insisting that the kingdom of God is advanced only by preaching the gospel, living in holiness, and bearing suffering rather than inflicting it. For them, the example of Jesus (who submitted to violence without retaliation) set the pattern for the church.
The result is a continuing tension within Christian thought: is it possible to wage a just war under God’s authority, or must Christians reject war entirely as incompatible with the way of Christ? The New Testament does not resolve the tension fully. It affirms both the state’s authority to wield the sword and the disciple’s duty to love enemies. That tension has shaped Christian debate for nearly two thousand years, and it continues today.
War in Modern Times
Modern wars expose not only the devastation of violence but also the power of perception. In almost every conflict, both sides see themselves as righteous. Governments present their wars as just, media outlets frame the narrative to inspire loyalty, and soldiers are told they are fighting for freedom, family, or even faith.
History shows how deeply this tension runs for Christians. In World War II, German Christians prayed for victory under their flag while Allied Christians prayed for deliverance from tyranny. Both sides read the same Bible, sang the same hymns, and asked the same God for protection, yet they were killing each other on the battlefield. Today, in the Russia–Ukraine war, believers in Ukraine cry out to God for rescue, while believers in Russia ask God to bless their soldiers. Both groups open their Bibles, both appeal to Scripture, and both are convinced they stand on the side of justice.
The same dynamic can be seen in the Middle East, where conflict is often cast in explicitly religious terms. Muslims, Jews, and Christians find themselves on opposing sides, each convinced that history, God, or justice is with them. Even in the West, after September 11, 2001, many Christians saw military action in Afghanistan and Iraq as righteous self-defense. At the same time, countless people in the Muslim world viewed those wars as Western aggression and believed they were resisting oppression.
The scale of those wars raises hard questions. According to Wikipedia’s summary of the War on Terror estimates suggest that the U.S. “War on Terror” has caused between 900,000 and 1,000,000 direct deaths since 2001, with broader studies including indirect effects such as famine, displacement, and disease placing the toll at more than 4 million. Other voices cite figures of 1.5 to 2 million, though these higher numbers are harder to verify. Whatever the final count, the scale of death is staggering. Was this response biblically justified as a war of defense and justice? Or did it cross into the category of murder by its disproportionate scope and civilian cost? These questions remain urgent for Christians who want to apply Scripture faithfully. They remind us that the Bible’s categories of justice, restraint, and love of enemy must be wrestled with in every age, especially when both sides of a conflict claim to be fighting for righteousness.
The Bible does not give a checklist to decide which nation’s cause is righteous. What it does give are categories and warnings. Paul affirms that governments “do not bear the sword in vain” (Romans 13:4), yet not every act of war is righteous. Jesus commands His followers to love their enemies and pray for their persecutors (Matthew 5:44), a command that forbids blind hatred and cautions against baptizing national interest as holy.
For Christians, the lesson is sobering: sincere believers can be found on opposite sides of the same conflict. That reality should humble us. It reminds us that human governments, media, and national myths cannot be trusted to define righteousness. Christians must measure every claim of justice against the Word of God, remembering that Christ’s kingdom is not of this world (John 18:36).
Modern Christians remain divided. Some see military service as a vocation of neighbor-love, protecting the innocent and restraining evil. Others believe that obedience to Christ requires rejecting all killing, even in war. Wherever we land, Scripture calls us to resist propaganda, test every claim of righteousness, refuse hatred, and seek peace in Christ above the narratives of nations.
Religious Killings vs. Political Killings
The Bible distinguishes between killings commanded by God for religious or covenantal reasons and killings carried out for political power. Israel’s executions of idolaters or blasphemers were tied to covenant holiness. In contrast, Jezebel’s murder of Naboth (1 Kings 21) or Herod’s beheading of John the Baptist (Mark 6:27) were abuses of political authority.
History shows that the Crusades and later religious wars often blurred the line between political power and spiritual mission. Medieval Christians, encouraged by popes and monarchs, claimed divine sanction for military campaigns to reclaim or defend the Holy Land. Many believed they were serving Christ by wielding the sword, yet the New Testament never authorizes the church to kill in His name. Under the New Covenant, the weapons of the church are spiritual, not physical (2 Corinthians 10:4).
The tragedy of the Crusades is that zeal for God’s cause was mingled with political ambition, economic gain, and national pride. Violence done under the banner of the cross became a stumbling block, leading many to confuse Christianity with conquest. The same was true of later wars of religion in Europe, where Protestant and Catholic states fought for dominance while ordinary believers suffered.
Scripture’s categories are clear: the state may bear the sword to punish evil (Romans 13:4), but the church’s calling is to bear witness, not arms. Whenever the church has forgotten this distinction, history has recorded deep scars.
The battlefield has always been a place of moral testing. Whether in Israel’s holy wars, Rome’s persecution, the Crusades, or modern conflicts, Christians have wrestled with whether killing in war can ever be righteous. Yet Scripture widens the lens even more. Beyond human armies and courts, it speaks about God Himself taking life – and even about when He allows it. That brings us to Part 3.
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