We are now in the third and final unit: The Holy Spirit and the Church. The first set of posts in this final unit was on the Holy Spirit. The second set was on the Church. The third set was on sacraments. This final section is on Christian ethics.
War should only be conducted under extreme circumstances.
The next five articles will look at "ending life" from the perspective of 1) war, 2) capital punishment, 3) self-defense, 4) euthanasia, and 5) abortion. We begin with the question of war. When, if ever, is war justifiable from a Christian perspective?
1. The Old Testament has plenty of war. The wars of conquest are not only allowed but commanded by God himself. In the case of Jericho, Israel is commanded to slaughter every living thing in the city, from male warriors to innocent children and animals (Josh. 6:17-21). The kings of Judah and Israel often engaged in war.
Those with the heart of Christ have often wrestled with God's commands for the conquest of Jericho.  We can believe that there was a reason for such a command at that moment in time and still find it incredibly puzzling given Jesus' teaching and commands in the New Testament. There are reasons for God's commands. Those who love the letter of the commands but do not have the heart of those commands do not truly keep the commands.
We have the Pharisees of Matthew as the best example of individuals who were more interested in the letter of the Bible than in the heart of God. It is the person that "likes" the story of Jericho's complete annihilation that is more likely to have a spiritual problem than the person who struggles with why God would command the slaughter of so many. No, those with the heart of Christ will almost certainly struggle with that dimension of this story.
2. War seems necessary, from a practical standpoint. Not to gain territory. Not because of some grander scheme where you think the end justifies the means. War seems necessary because the hearts of men are evil. War seems necessary to stop the advancement of the conqueror. War seems necessary to stop the atrocities of men. If there were no sin, there would be no war.
These are not evil motivations--the protection of others, the elimination of a cancerous evil. They do not contradict the love of God, of neighbor, or enemy.
Of course most of us will never have the decision for war within our power. In most countries, those decisions are delegated to people we elect. We do have a choice in who we vote for. We can vote for people who have a heart for war or we can vote for people who see war as a course of last resort.
But it is worth asking, "What would God do?" The question, "What would Jesus do?" is a slightly different one. While on earth, Jesus modeled an ethic for an individual living in a conquered domain. The question of war is more a question of government, a question for the opposite side of the equation, a question for Israel in control of its land. It is a question for God as the empowered judge or the enthroned Christ when he returns as king.
God is love. We have argued in a previous article that God's justice fits within the context of his love. There we suggested three ways in which love might call for justice or at least not contradict it. These were 1) justice for redemption, 2) justice for protection, 3) justice as removal. Insofar as war is compatible with Christ, it will fall within one of these three categories.
3. Before we look at those three justifications for war, we should stop and remind ourselves of Jesus' core ethic. God's ethic does not contradict Jesus' ethic. It only plays it out on a larger scale.
Jesus' ethic consisted of the twin love command: love God and love neighbor: "On these two commandments hang all the law and the prophets" (22:40). Similarly, "In everything do to others as you would have them do to you; for this is the law and the prophets" (7:12).
Perhaps even more to the point is Matthew 5:43-48: "“You have heard that it was said, You must love your neighbor and hate your enemy. But I say to you, love your enemies and pray for those who harass you so that you will be acting as children of your Father who is in heaven... If you love only those who love you, what reward do you have? Don’t even the tax collectors do the same? ... Therefore, just as your heavenly Father is complete in showing love to everyone, so also you must be complete" (Matt. 5:43-44, 46, 48 CEB).
The Parable of the Good Samaritan gives an illustration of this principle. A Samaritan, an "enemy," demonstrates the love principle by showing mercy on a Judean. Jesus thus does not give us permission to do whatever we want to our enemy. He does not consider our enemy guilty simply because he or she is our enemy.
4. The implementation of war always involves the violation of the love command, because the heart of man is evil. There will almost always be those who do atrocities in war. Most of those engaged in battle will use hatred to direct their energies.
The imprecatory psalms cannot be used to justify hatred of one's enemies, for Jesus is a higher authority than the Psalms. The imprecatory psalms show us that we can be angry at injustice. They cannot be used to justify hatred.
For these reasons, war must be reserved for the most extreme of circumstances, for it is a source of temptation to do evil on the greatest of scales. It must only be enacted with the purest of motives and the greatest of reserve. Only then do the combatants have a better chance of engaging in battle with a pure heart.
Nevertheless, God can use the wicked in heart as well. He used King Cyrus in this way (Isa. 45:1). He used Pharaoh in this way (Rom. 9:17). He can use the wicked of heart in battle.
The Roman Catholic Catechism warns wisely that a people should not go to war unless "all other means of putting an end to it [an aggressor] must have been shown to be impractical or ineffective" (2309). 
5. The decision for war should thus be reserved for the direst of circumstances. The first love basis for justice is justice for redemption, to help lead a person away from a self-destructive trajectory. On a corporate level, a people might be in dire need of freedom from a tyrant. A people, as it were, might need redeemed from individuals within their own ranks.
In Judges, God often raised up individuals to free Israel from foreign rule. We should also remember that it was Israel's sin that regularly put themselves into slavery in the first place. So war may be justifiable in some circumstances as a "war of redemption."
However, let us be clear that war seldom accomplishes its goal without unintended consequences of an evil nature. The Catholic Catechism warns that "the use of arms must not produce evils and disorders graver than the evil to be eliminated. The power of modern means of destruction weighs very heavily in evaluating this condition" (2309). From all appearances, we can probably point to several recent "wars of redemption" whose effects have been worse than the evil they sought to address.
6. Most just wars are "wars of protection." They are wars in which a nation engages to protect itself from an aggressor. The Roman Catholic Catechism puts it in this way: "the damage inflicted by the aggressor on the nation or community of nations must be lasting, grave, and certain" (2309). In other words, there must be certainty that the aggressor intends to inflict lasting and grave damage to your people. There needs to be a "clear and present danger."
7. Occasionally, an aggressor arises of such complete depravation that a "war of removal" or a "war of annihilation" arises. This is a war against such depravity that there is no good in the enemy, no chance of redemption. We must have great caution here, for every war thinks its enemy of this sort.
Yet there were many Germans who did not support Hitler or who did and were redeemed after World War 2. Hitler himself was likely a reprobate, hardened beyond redemption. Many of those who led with him and lead his regime were likely of this sort. But there were others who were not. So there is a sense even in the case of World War 2 that it was a war of redemption as well as a war of protection. The German people were redeemed.
8. We can thus sum up the criteria for what we might call a "just war." 
- It is a course of last resort. All other reasonable attempts at peace need to have been tried. There needs to be a clear and present danger.
- It needs to be done with a loving motivation, either to redeem a people or to protect against a power actively engaged in harm of the highest magnitude.
- It needs to be conducted in such a way that the consequences are not likely to be a greater evil than the evil against which the war is conducted in the first place.
War should only be engaged under the most extreme of circumstances, when the decision for war can be done in harmony with the love command.
Next Sunday: ET9: Capital punishment should be reserved for extreme circumstances, if used at all.
 Adam Hamilton is just one recent attempt. He works at "making sense of this violence without justifying it," in Making Sense of the Bible: Rediscovering the Power of Scripture Today (New York: HarperCollins, 2014), 215.
 The Roman Catholic Catechism, especially 2309.
 Just war theory finds its real origins in the writings of St. Augustine in his City of God (e.g., 22.6) and it was refined by Thomas Aquinas in his Summa Theologica.