Indeed, we live as human beings, but we do not wage war according to human standards; for the weapons of our warfare are not merely human, but they have divine power to destroy strongholds. We destroy arguments and every proud obstacle raised up against the knowledge of God, and we take every thought captive to obey Christ.
- 2 Corinthians 10:3-5
What struck me as I was reading this passage was not the "spritual warfare" language; after all, this is not the only NT passage that uses that metaphor. What struck me is the explicit contrast between physical warfare ("war according to human standards") and spiritual warfare.
In one sense, this contrast is nothing special: the same physical/spiritual contrast is used in other contexts, e.g. "letters of recommendation" vs. "letters written on our hearts" in 2 Corinthians 3:1-2, or physical circumcision vs. circumcision "of the heart" in Romans 2:26-29. In each case, Paul uses scenes from everyday life to draw analogies about spiritual life.
But underlying Paul's arguments is the (sometimes explicit, sometimes implicit) acknowledgement: Spritual life is not quite like that. In this example, Paul makes it explicit: "We do not wage war according to human standards." [emphasis mine]
The book of Revelation provides a striking image of this contrast:
and in the midst of the lampstands I saw one like the Son of Man, clothed with a long robe and with a golden sash across his chest. His head and his hair were white as white wool, white as snow; his eyes were like a flame of fire, his feet were like burnished bronze, refined as in a furnace, and his voice was like the sound of many waters. In his right hand he held seven stars, and from his mouth came a sharp, two-edged sword, and his face was like the sun shining with full force.
- Revelation 1:13-16
"From his mouth came a sharp, two-edged sword" -- the language is reminiscent of Hebrews 4:12, "Indeed, the word of God is living and active, sharper than any two-edged sword, piercing until it divides soul from spirit, joints from marrow; it is able to judge the thoughts and intentions of the heart." In both places, the two-edged sword is associated not with physical might but with spoken words.
And yet so many Christians throughout the ages have gotten it wrong. From Constantine, through the Crusades, to George W. Bush's invasion of Iraq, Christians have for centuries tried to justify military aggression in the name of God.
Will Christians ever learn to be peacemakers and earn the title, "children of God" (Matthew 5:9)? Or don't we have any good news to offer a violent world?