James, the brother of Jesus, wrote a letter to some Christian churches scattered throughout the Roman empire in which he asked, "What causes wars and what causes fightings among you? Is it not your passions which are at war in your bodies? You desire and do not have; so you kill. You covet and cannot obtain; so you fight and wage war." In other words, the origin of hostile conflict, whether among nations or neighbors, is frustrated desire, "You desire and do not have, so you kill."
The weary father desires peace and quiet but the children are all excited with a new game, and so he lashes out in anger. The college senior desires to get married, but his fiancee breaks the engagement, and so for months he swings between depression and rage. A political party desires to control the legislature, but lacks superior candidates, so it smears the opposition. A nation desires a safer border, so it invades another land. "You desire and do not have, so you kill"—or steal, or exploit, or lie, or grumble, and peace vanishes out of the world.
But Jesus said "Blessed are the peacemakers" (Mt. 5:9). St. Paul said, "If possible, so far as it depends on you, live peaceably with all" (Rom. 12:18). And the apostle Peter said, "Seek peace and pursue it" (1 Peter 3:11). Over and over in the Bible God is called the "God of peace"" (Rom. 15:33; 16:20; Phil. 4:9; Heb. 13:20; 1 Thess. 5:23; 2 Thess. 3:16). Jesus is called the "Prince of Peace" (Is. 9:6). His message is called the "gospel of peace" (Acts 10:36; Eph. 6:15). And in the new age, which he promises to bring, "justice and peace will kiss" each other (Psalm. 85:10).
So there's a big question: How can we follow Jesus in the way of peace when our hearts are brimming with desires and longings which often go unfulfilled? I don't think there is any way to make a human being cease to have desires. You wouldn't want to do it if you could. It's true that a person without desires wouldn't make war, but he wouldn't make love either—or poems, or birthday parties, or roads or hospitals. The answer is not in quenching desire. The answer is in redirecting desire towards God who promises ultimate satisfaction.
Isn't it true that when a person becomes abusive or hostile it's because he's not resting in the promise of God to work all things together for his good? The reason there are so many angry and hostile and militant people in the world, is because there aren't very many people who really believe that the living God is at work in every situation for the good of those who trust him. And yet the great prophet Isaiah said, "No eye has seen a God besides Thee, who works for those who wait for Thee" (Is. 64:4). And Jesus said, "Don't be anxious; your Father knows your needs; seek first his Kingdom, and he'll give you what you really need" (Mt. 6:31-33).
The gospel of peace does not demand that we cease to desire, but that we direct our desire towards God and discover that the promises purchased for us by Jesus Christ on the cross and secured for us by his resurrection—these promises are satisfying beyond measure.
Therefore, if you want to be a peacemaker, your first item of business is to have confidence that God works everything together for the good of those who love him. And then, when your heart is freed from fear and guilt and greed, you can pray with genuine love that the leaders of the world will turn their desires to the living God and find the peace which passes all understanding for themselves and for the nations.