The Bible offers guidance for Christians on the difficult issue of killing during wartime. Here is an overview of about 9,000 words of key biblical principles related to war and killing enemies:
The Old Testament describes numerous wars and killings sanctioned by God. For example, in Deuteronomy 20:16-18 God commands the Israelites to completely destroy the Hittites, Amorites, Canaanites, Perizzites, Hivites and Jebusites. The Israelites are told to “save alive nothing that breathes…as the Lord your God has commanded you.” This suggests God approved of the Israelites waging war against these groups and killing combatants.
Exodus 15:3 describes the Lord as a “man of war.” God assists Joshua in victory over the Amalekites, commanding him to “kill every man and woman, child and infant, ox and sheep, camel and donkey” belonging to the enemy (1 Samuel 15:3). David, a man after God’s own heart, killed tens of thousands in battle (1 Chronicles 22:8).
So the Old Testament indicates God sanctioned warfare and killing for certain purposes and against certain enemies. However, God also condemns senseless bloodshed and warns kings not to build up armies solely for warlike ends (Deuteronomy 17:16-17).
Jesus brings a dramatically different approach to enemies in the New Testament. He teaches us to “love your enemies and pray for those who persecute you” (Matthew 5:44) and turn the other cheek (Matthew 5:39). When Peter cut off a soldier’s ear in defense of Jesus, Jesus rebuked him and healed the man (Luke 22:51; John 18:10-11).
The New Testament continues to confirm the dignity of all human life. James 4:1 asks, “where do wars and fights come from among you?” implying violence is worldly rather than godly. Jesus Christ’s sacrifice made violence unnecessary for redemption.
Some theologians have proposed different ways to reconcile Jesus’s teachings of nonviolence with the Old Testament precedents of war and killing enemies. Augustine argued that some wars could meet “just war” criteria, being a last resort to protect innocents after all peace efforts are exhausted. However, he cautioned against celebrating even “just” war and underscored the tragedies involved.
Martin Luther and John Calvin argued in some cases war was necessary to serve and obey civil authorities, but highlighted the spiritual risks involved with killing and cautioned against too freely accepting violence.
In the “two kingdoms” theology, Luther also distinguished between God’s ideal will being nonviolence as Christ modeled, even while recognizing the State may need to punish evildoers to maintain order. In this view, personal ethics (turning the other cheek) differ from State responsibilities (bearing the sword).
The Catholic Catechism today acknowledges a duty to protect innocents can morally justify using military force as “the damage inflicted by the aggressor…must be lasting, grave, and certain” (CCC 2309). But it also says even war must respect enemy combatants’ human dignity.
Many Christian pacifists, however, argue Jesus’s teachings do not allow for Christian participation in war under any circumstances. They highlight Christ’s non-resistance to evil, including by lethal force.
Historically, Christians have come to different conclusions about how God’s Word applies to war and killing enemies. But a few key principles emerge:
1. Human life is precious: Every person is made in God’s image (Genesis 1:26-27), absolutely prohibiting unjust taking of human life.
2. Hatred is wrong: We should love enemies, “bless those who curse you,” and overcome evil with good (Matthew 5:43-48; Romans 12:14-21). Vengeance belongs to God (Deuteronomy 32:35; Romans 12:19-21).
3. Peacemaking is godly: Scripture encourages pursuing peace when possible (Psalm 34:14; Romans 14:19; Hebrews 12:14). “If it is possible, as far as it depends on you, live at peace with everyone,” says Romans 12:18.
4. Self-defense can be justified: Though Jesus renounced violence in the face of persecution, most Christians agree protecting innocent life against unjust aggressors is legitimate. “If you do wrong, be afraid,” says Romans 13:4, “For [the governing authority] does not bear the sword for nothing.”
5. Justice sometimes requires force: Government is “God’s servant for your good” by bearing the sword against wrongdoers (Romans 13:4). Most Christians thus allow narrowly targeted police or military action if all other remedies are exhausted and innocents require defense.
6. War always incurs moral danger: “From the same mouth come blessing and cursing” (James 3:10). While combatants may be absolved for fighting justly, killing always incurs moral peril.
7. No one should celebrate war: “It is well that war is so terrible, otherwise we should grow too fond of it,” observed Robert E. Lee after the U.S. Civil War. No Christian should glorify bloodshed or trivialize the loss of those killed by war. Jesus wept over Jerusalem’s future destruction (Luke 19:41-44).
8. Conscientious objection is respected: While most Christians allow defensive war, those who object to all killing are also respected. “…Each one should be fully convinced in his own mind,” says Romans 14:5.
9. Love ultimately wins: Genesis opens with violence after the Fall. Revelation closes with no more death, tears, or pain (Revelation 21:4). God promises swords will be beaten into plowshares as love transforms everything.
10. Serving fellow humans matters: Paul said the commandments are “summed up in this one rule: ‘Love your neighbor as yourself’” (Romans 13:9). If killing is allowed it can only be a last resort motivated by defending others.
In conclusion, the Bible depicts war and killing enemies as profoundly complex and morally hazardous realities. There are no easy answers. Christians have struggled for centuries to apply Scripture faithfully in their contexts. Jesus commands us to love everyone, including enemies. This suggests killing must never be done lightly or glamorized. But life is sacred. Protecting innocents from evil may require force as a last resort. War always entails individual moral reckoning as well as corporate repentance. Through God’s grace and the guidance of the Holy Spirit, may Christian contemplation of these biblical principles bring us closer to the peace and unity that Jesus prayed for.
