Living Christianity: The Ten Commandments (Safeguarding Human Life, Part 2)

March 19, 2019

by Peter Amsterdam


As we saw in the previous article, the sixth commandment, Thou shalt not kill, allows a person to morally use self-defense to protect their life as well as the lives of others. What happens when that principle is projected on a larger scale? Is it morally right for a government to order its military to kill their country’s enemies in a time of war, and is it moral for the soldiers to obey those orders? Is it moral to fight a defensive war when attacked by another country? Is it ever moral for a country to start a war?

Before addressing the moral and ethical issues of war, it’s important to understand that while some Christians in the past went to war for religious purposes, such wars were wrong and immoral. Christians are not called to advance Christianity in general, or a specific denomination, by means of warfare. Believers are called to use spiritual warfare against Satan and his influence in our lives.

Put on the whole armor of God, that you may be able to stand against the schemes of the devil. For we do not wrestle against flesh and blood, but against the rulers, against the authorities, against the cosmic powers over this present darkness, against the spiritual forces of evil in the heavenly places. Therefore take up the whole armor of God, that you may be able to withstand in the evil day, and having done all, to stand firm.1

Though we walk in the flesh, we are not waging war according to the flesh. For the weapons of our warfare are not of the flesh but have divine power to destroy strongholds.2

Scripture describes the time after Jesus’ second coming as a time of peace.

Out of Zion shall go the law, and the word of the LORD from Jerusalem. He shall judge between the nations, and shall decide disputes for many peoples; and they shall beat their swords into plowshares, and their spears into pruning hooks; nation shall not lift up sword against nation, neither shall they learn war anymore.3

While we can look forward to such an idyllic time in the future, sadly the world today is one in which the evil ravage of war exists. As one military man stated, War is hell.4

There are differing opinions among Christians when it comes to the morality and ethics of war. Some consider that Christians are obligated to obey their government by participating in their government’s wars, since government is ordained by God. This point of view is sometimes referred to as activism. Other Christians feel that believers should never participate in war, a view which is called pacifism. Yet others believe that Christians can participate in their government’s just wars but not their unjust wars, which is sometimes called selectivism, and more often referred to as the just war view. A brief explanation of each of these views follows.


Scripture teaches that civil government is ordained by God with the responsibility to protect its citizens. A concept expressed in the book of Genesis after the flood is seen as a judicial basis for taking the lives of those who unjustly kill others.

From his fellow man I will require a reckoning for the life of man. “Whoever sheds the blood of man, by man shall his blood be shed, for God made man in his own image.”5

In Romans 13, which we went over earlier in this series, we read that governmental authority is instituted by God and that it is God’s servant for your good. But if you do wrong, be afraid, for he does not bear the sword in vain. For he is the servant of God, an avenger who carries out God’s wrath on the wrongdoer.6 The apostle Peter wrote:

Be subject for the Lord’s sake to every human institution, whether it be to the emperor as supreme, or to governors.7 

Elsewhere in the New Testament, we also find that God has ordained civil government and that it should be obeyed.8

The activism view is that because government is ordained by God, to disobey the government is to disobey God. Therefore one ought to respond when their government calls for its citizens to participate in defense of their country, even though that may require them to kill other human beings.


Christian pacifism holds the view that killing is always wrong, and therefore it is never right for a Christian to participate in war. This belief is rooted in the sixth commandment, You shall not kill,9 as well as Jesus’ instruction, Do not resist the one who is evil.10 The foundation of Christian pacifism is that the intentional taking of someone’s life is murder, and murder is always wrong. Since the nature of war is to kill others, it is inherently wrong and immoral, and therefore Christians should never take part in war.

Christian pacifists face the challenge of Old Testament texts which sometimes command war. Some pacifists argue that wars were commanded by God in the same sense in which Moses allowed divorce—because of the hardness of people’s hearts. Jesus said:

Because of your hardness of heart Moses allowed you to divorce your wives, but from the beginning it was not so.11

Their position is that God does not desire or command war any more than He likes divorce. Wars in the Old Testament were not God’s perfect will, but only His permissive will.

One author wrote:

A basic premise of pacifism is that there is no real distinction between what one should do as a private citizen and what one should do as a public official. What is wrong for a person to do in one’s own neighborhood is wrong in any other neighborhood in the world. Putting on a military uniform does not revoke one’s moral responsibility. … No person is exonerated from God’s command not to kill simply because they have changed uniforms. The command against murder is not abrogated by one’s obligation to the state. Only God holds the power of life and death.12

Selectivism (Just Wars)

In contrast to both activism (the position that it’s always morally right to fight wars at the command of your government) and pacifism (the position that it’s never morally right to fight wars), selectivism is the concept that some wars are morally justifiable, and therefore it is morally right to fight them. This is often referred to as “Just War Theory.”

If some wars are just and others are unjust, the selectivist view is that it is justifiable for a Christian to fight in the just wars, but not the unjust ones. Throughout Scripture, we find instances where God’s people rightly disobeyed their government when the laws contradicted God’s moral law.13 However, Scripture also teaches that governments are responsible to restrain evil and to punish those who do evil. The apostle Paul wrote that governments are to “bear the sword” against evildoers.14 Civil governments are tasked with protecting their citizens from criminals, and it stands to reason that they would also be responsible to protect their citizens from aggressor nations that attack their country.

St. Augustine (354–430 AD) is generally considered to be the first Christian to put forth a theory on war and justice, building on the teachings of some Greek and Roman philosophers. He made the point that some wars are necessary in order to rectify an evil. Later, St. Thomas Aquinas revised Augustine’s teaching by putting forth three criteria for a just war. In time, this developed into the Just War Theory, a moral justification for going to war as well as a definition of moral conduct during a war.

Just War Theory attempts to address three truths, which can seem to be incompatible:

  • Killing another human being is wrong.
  • Government has a duty to protect its citizens and defend justice.
  • Protecting innocent human life and defending important moral values sometimes requires using force and violence.

Just War Theory seeks to define the conditions that need to be met in order to determine whether it is morally justifiable to go to war; and if war is conducted, the moral and ethical manner in which it should be fought. The purpose of the theory isn’t to justify going to war, but to prevent or at least minimize the scope of war by showing that it is only legitimate in certain circumstances, barring which it is immoral. The key premise is that war is always bad, but a just war can sometimes be the lesser of two evils.

Below are the criteria which, according to the Just War Theory, must be met for a war to be just. These address both the moral requirements for going to war in the first place, as well as the manner in which a war is to be conducted. (The examples given express a general idea of what’s involved in the criteria for a just war, though they are more complex and detailed than what is stated here. It’s also important to note that the criteria can be manipulated by governments who are looking to justify an unjust war.)

Just cause

When a country is attacked by another country, it is just for the attacked country to go to war in self-defense. Another scenario where going to war can be acceptable is when a country is massacring large numbers of its own people. In such a case, another country can step in militarily to stop the massacres.

Just authority

Scripture teaches that God gave the “sword” to governments, and not to individuals; thus only a war that is declared by the proper governmental authorities can be considered legitimate. It is the properly constituted governmental authorities who are responsible for judging whether the criteria for going to war are met.

Last resort

Before a war is declared, all means of nonmilitary prevention—such as diplomacy, negotiation, conflict resolution, etc.—must be exhausted. The only thing that can justify the brutal killing that war will bring is if every legitimate means of prevention has failed.

Just intention

A war is only a just war if it is fought for the right intention. Wars fought for national glory, revenge, grabbing land, enslaving people, seeking power, hatred of one’s enemies, genocide, or preserving colonial power are immoral because the intentions of the war are immoral. Wars fought for right intentions such as creating, restoring, or keeping a just peace, righting a wrong, or assisting the innocent are considered just wars. The primary objective of a just war should be to reestablish peace; and the peace which comes after the war should be greater than the peace which could have been achieved by not going to war.

Probability of success

Fighting a war that will inevitably result in massive casualties, destruction, and death, with no reasonable hope of success, no matter how just the cause, is not moral. The American War against Vietnam is an example. The Pentagon Papers revealed that the Pentagon had calculated in advance that there was not a reasonable chance of success in the Vietnam War—and they were right.15

Proportionality of cost

The goal of the war should be in proportion to the offense. For example, if country A invades country B and annexes a portion of that country, then country B has the right to recover the land that was taken. However, it is unethical for country B to carry on the war in order to fully conquer country A. Another way to understand this is that the benefits of waging the war must be in proportion to the cost: a war must prevent more evil than it causes, and it must prevent more suffering than it costs.

Formal declaration

When the government of a nation decides to fight a war, it is responsible to announce its intention to make war as well as conditions which would avoid it. Informing the other nation of the conditions for avoiding war enables them to know what they must do to prevent the war. This formal declaration also allows the citizens of the country which is declaring war to know why their government is going to war on their behalf, thus allowing the population to consider the justice of the war in comparison to the killing and destruction it will bring. It provides transparency, so the citizens will know what the government is doing in their name.

Fought justly

Even if a war is just, not all actions involved in fighting the war are necessarily just. Using chemical agents, for example, is inhumane. Torturing prisoners is immoral. Intentionally killing women and children and other noncombatants is unjustified. Some noncombatants are always killed in war, but it is immoral to target them.

Terrorism—the practice of attacking whoever happens to be in a target location such as a store, building, etc.—is not a moral means of conducting war, as it specifically targets civilians and not military facilities. If a country’s military purposely attacks civilians’ homes, villages, or neighborhoods, this is considered state terrorism.

In summary, the selectivist position is that if a war is clearly unjust, then it is morally wrong for a Christian to fight in it or to support it. While Christians are commanded to obey civil government, when such a government commands them to commit immoral acts, they are not bound to obey. In such situations, the biblical principle of “We must obey God rather than men”16 applies. Refusing to participate in a country’s war when military service is required will likely have consequences.

If when you do good and suffer for it you endure, this is a gracious thing in the sight of God.17

War is a terrible undertaking, and is waged by governments for a variety of reasons—some just and some unjust, some moral and others immoral. Any government which commits its country to war is most likely going to offer reasons for doing so, and will present them as being just and moral. In some cases, they are genuinely just; in others, explanations are crafted to sound as if the war is being fought for just reasons, when in fact that is not the case. As a Christian, it’s wise to prayerfully consider whether your government is justified in a war it wages; and if not, then to use legal means to protest and do your part to elect different people to govern.


Unless otherwise indicated, all scriptures are from the Holy Bible, English Standard Version, copyright © 2001 by Crossway Bibles, a division of Good News Publishers. Used by permission. All rights reserved.

1 Ephesians 6:11–13.

2 2 Corinthians 10:3–4.

3 Isaiah 2:2–4.

4 Attributed to Gen. William Tecumseh Sherman, a general in the American Civil War.

5 Genesis 9:5–6.

6 Romans 13:4.

7 1 Peter 2:13–14.

8 For more on God-ordained civil government, see The Ten Commandments: Authority, Parts Two and Three.

9 Exodus 20:13 NAS.

10 Matthew 5:39.

11 Matthew 19:8.

12 Norman L. Geisler, Christian Ethics (Grand Rapids: Baker Academic, 2010), 227.

13 See Daniel chapters 3 and 6; Acts chapters 4–5; Exodus 1:17, 20–21.

14 Rulers are not a terror to good conduct, but to bad. Would you have no fear of the one who is in authority? Then do what is good, and you will receive his approval, for he is God’s servant for your good. But if you do wrong, be afraid, for he does not bear the sword in vain. For he is the servant of God, an avenger who carries out God’s wrath on the wrongdoer (Romans 13:3–4).

15 Glen H. Stassen & David P. Gushee, Kingdom Ethics (Downers Grove: IVP Academic, 2003), 161.

16 Act 5:29.

17 1 Peter 2:20.