There is nothing in the New Testament that promotes war or violence. Listen to Jesus speaking of the attitudes handed down to his listeners:
You have heard that it was said, “An eye for an eye and a tooth for a tooth.” But I say to you, Do not resist an evildoer. But if anyone strikes you on the right cheek, turn the other also; …You have heard that it was said, “You shall love your neighbor and hate your enemy.” But I say to you, Love your enemies and pray for those who persecute you, so that you may be children of your Father in heaven; for he makes his sun rise on the evil and on the good, and sends rain on the righteous and on the unrighteous.
(Matthew 5:38-39;43-45)
The closest Jesus comes to a violent action is chasing the moneychangers out of the temple, which can hardly be compared to dropping bombs on them. When Jesus is arrested, though, one of his companions, who had misunderstood the sword image Jesus had used (see Luke 22:36 ), cuts off the ear of the high priest’s slave. Far from being pleased, Jesus says, “No more of this!” – and heals the ear (Luke 22:49-51).
In fact, the war imagery used in the New Testament has been flipped upside down so that it no longer points toward violence but toward faith and love.
“Put on the whole armor of God,” we read in Ephesians 6.
Yes, get ready to battle evil. But what is this armor? What are the weapons? Not something you could buy from a gun dealer or a military supply store.
Stand therefore, and fasten the belt of truth around your waist, and put on the breastplate of righteousness. As shoes for your feet put on whatever will make you ready to proclaim the gospel of peace. With all of these, take the shield of faith, with which you will be able to quench all the flaming arrows of the evil one. Take the helmet of salvation, and the sword of the Spirit, which is the word of God.
(Ephesians 6:14-17)
What we have here is a verbal beating of swords into plowshares. The earliest Christians understood this transformation and generally refused to serve in the army. What a long way we have come from our origins.
what about when he said, “I come not to bring peace, but the sword”?
Jesus is talking about the response his followers are going to get – often a hostile response, even from family and friends. (See the next verses, Matthew 10:35-36, for examples.) In fact, almost all of the initial group of apostles ended up being martyred.
In my own life, when I told my parents that I was planning on entering religious life, my mother asked, “What are we going to tell the neighbors?” You would have thought I had told her I was planning on moving to a brothel. This was not a violent response, but not warmly accepting either. (Years later, though, at the time of my final vows, she told me, “I feel better about your being in the Cenacle, because I can tell that they love you.”)