Satan’s aim is that no one be saved and come to a knowledge of the truth. And one of his key strategies is to start battles in the world that draw our attention away from the real battle for the salvation of the lost and the perseverance of the saints. He knows that the real battle, as Paul says, is not against flesh and blood. So the more wars and conflicts and revolutions of “flesh and blood” he can start, the better, as far as he is concerned.
So when Paul tells us to pray for peace precisely because God desires all men to be saved and to come to a knowledge of the truth, he is not picturing prayer as a kind of harmless domestic intercom for increasing our civilian conveniences. He is picturing it as a strategic appeal to headquarters to ask that the enemy not be allowed to draw any firepower away to decoy conflicts of flesh and blood.
—John Piper, Let the Nations Be Glad