What does the Bible say in the New Testament about killing in war? Is killing in war a sin?
First of all, the New Testament does not directly address these questions. But it does speak of a “war in heaven” in Revelation 12:7, “And war broke out in heaven: Michael and his angels fought with the dragon; and the dragon and his angels fought” (NKJV). In Revelation 19:11 we read; “Now I saw heaven opened, and behold, a white horse. And He who sat on him was called Faithful and True, and in righteousness He JUDGES AND MAKES WAR.” This verse is speaking of the return of the Lord Jesus Christ to earth as King of kings and Lord of lords and in order to prepare the world for His 1,000 year reign He will “make war” with His enemies.This “war” ends with what we see in verse 21, “And the rest were KILLED with the sword which proceeded from the mouth of Him who sat on the horse.” This proves that war and killing in war is sometimes NECESSARY and that instead of being a sin, it is JUST.
We could cite multiple examples from the Old Testament that illustrate the same truth; war is, at times, NECESSARY and JUST. I would encourage you to read Joshua 8:1-2; 1st Samuel 15:3 and 2nd Samuel 5:23-24 where God commanded His people to go to war and to kill their enemies.
What about the Christian? Should a believer in Christ “go to war” and “kill our enemies?” There are two main views held by Christians which we will now consider. We will leave it to the reader to decide which view is right according their own conscience.
1) The PACIFIST VIEW is the belief that “war and killing in war is not justified under any circumstances.” The PACIFIST will point to Matthew 5:38-39 to support this view; it says, “You have heard that it was said, ‘An eye for an eye and a tooth for a tooth.’ But I tell you not to resist an evil person. But whoever slaps you on your right cheek, turn the other to him also” (NKJV). They will also cite verses 43-44, “You have heard that it was said, ‘You shall love your neighbor and hate your enemy.’ But I way to you, love your enemies, bless those who curse you, do good to those who hate you, and pray for those who spitefully use you and persecute you.” In this view killing your enemy in combat would contradict the Lord’s teaching to “turn the other cheek” and to “love your enemies.” They also refer to Romans 12:17-19, “Repay no one evil for evil. Have regard for good things in the sight of all men. If it is possible, as much as depends on you, live peaceably with all men. Beloved, do not avenge yourselves, but rather give place to wrath; for it is written, ‘Vengeance is Mine, I will repay,’ says the Lord.”
2) The JUST WAR VIEW takes into consideration what we saw earlier, that “war is sometimes NECESSARY and JUST.” Those who hold this view cite the passages in Revelation which we already considered which prove that our Lord Jesus Himself will engage in war and kill His enemies. Their response to the verses quoted by the PACIFIST would be that there is a DISTINCTION BETWEEN A CHRISTIAN’S PRIVATE AND PUBLIC VIEWS. They would say that Romans 12:17-19 presents the responsibility of a Christian in his PRIVATE LIFE, but then they would turn to Romans 13:1-4 to show the Christian’s responsibility in PUBLIC LIFE. That passage states, “Let every soul be subject to the governing authorities. For there is not authority except from God, and the authorities that exist are appointed by God. Therefore whoever resists the authority resists the ordinance of God, and those who resist will bring judgment on themselves. For rulers are not a terror to good works, but to evil….For he is God’s minister to you for good….he does not bear the sword in vain; for he is God’s minister, an avenger to execute wrath on him who practices evil” (NKJV). In short, this view holds that as citizens of a country, we are to OBEY OUR GOVERNMENT WHICH WORKS FOR JUSTICE AGAINST EVIL. If a Christian is called upon by his/her country to fight in a war do combat evil, they should not resist but be willing to join the military and be willing to kill their enemies as an act of justice. (204.1) (DO)