The Bible records many occasions of wars, ranging from civil wars (2 Samuel 3:1) to conquering entire nations (1 Samuel 15:3). But God has also given a specific command not to “kill” or “murder” (Exodus 20:13). An important question for Christians, then, is whether killing in war is sometimes permissible or always sinful?
In this verse, God wants King Saul to wipe out an entire nation, including women and children. Saul ended up killing everyone except for their king. This was a very tragic event, but it was commanded by God. If we trust that God would never tell us to partake in sin, we must deem that killing in war, while ultimately terrible, is allowed by God in some situations.
In the Bible, war was sometimes necessary for the purging of evil. God sought to eliminate nations and practices which would lead his people away from him. As their Creator, God loves and respects all people, so he does not flippantly prescribe killing in war. But because he is holy, he cannot stand for the celebration of evil. Just as God will one day execut justice on all evil, so too in the Old Testament were the people of God commanded at times to act as the instrument of God’s judgment on the nations.
Some biblical interpreters take this passage to speak to a great war when Jesus returns, wherein he will execute judgment on evildoers. The enemies of God will be either thrown into the lake of fire or slain by the sword.
The verdict of sinfulness is ultimately up to God, even in the case of killing someone in war or otherwise. Because sin is a matter of the heart that expresses itself in actions, there could be occasions where killing in war is a sin and occasions when it is not. This type of sin would be particular to the individual and must be handled by God. The Bible, however, commands us not to hate others—all people are created in God’s image. Performing the duties of a soldier can be done, though perhaps with great difficulty at times, without hating the enemy. Even enemy soldiers are created in God’s image, and they themselves are often carrying out the actions of superiors whose intentions, for good or evil, will be judged by God at the end of the age.
The word translated “kill” in Exodus 20:13 (rāṣaḥ) speaks most prominently to muder and negligent homicide. In the event of a just war—and particularly, in the Bible when God commands his people to take the lives of others in judgment—it is not a sin to kill in war.
Although it may not be a sin to kill in war, there are often detrimental effects, both personally and corporately. In the Old Testament, David was not allowed to build God’s temple because he had shed much blood in war. It was a very serious matter to God.
It is important to note that because of Christ’s work, killing in war does not keep a Christian from access to God’s holy temple. Christians are covered by Jesus’ sinless blood and are able to approach God’s throne with confidence (Hebrews 4:16).
There are occasions where war is justified in the Bible:
The apostle Peter commands believers to be submitted to the commands of the nation, nations who bear responsibility for protecting and defending the people within a nation, as well as “punishing evildoers.” Believers should obey the government so long as the state does not encourage believers to disobey a clear command of God.
In this respect, war is to be seen as a last resort when terms of peace are rejected.
It can be considered just for soldiers to fight in a war when the war is the government’s means of punishing wrongdoing.
Although there are occasions when war can be justified, especially for soldiers who are commanded by a government to fight, theories for what counts as just war for nations are debated.
It is biblically acceptable to defend yourself against criminal activity carried out against you or your household. In such a situation, killing in self-defense is biblically allowed. While killing is a tragedy, the Bible considers the defender “not guilty” in most situations.
As Jesus makes clear in the book of Matthew, if a Christian is being persecuted for their faith, the Christian is called to endure suffering for Jesus’ sake.
There are examples of soldiers in both the Old and New Testament who loved God and had faith in Him. God also loved soldiers and never chided them for their profession or asked soldiers to find new jobs.
John the Baptist told soldiers to be content and to do no violence to people. Most scholars argue that this word for “violence” (diaseiō) means to “extort money through violence.”
Paul often used the image of warriors and battle as an example of the importance and serious nature of putting sin to death. The Christian battle of the mind is not fought by the flesh alone. Christ fights on our behalf. Our weapons have divine power and are able to defeat any sin that has taken root in us.
The New Testament also contains numerous examples of centurions who are at times regarded as “God-fearing men.” (Matthew 8:10; Acts 10:22).
Though war is a part of the fallen world, it will not take place in the renewed world where there will be no more tears or death (Isaiah 2:4; Revelation 21:4).