From Tim Keller’s Walking With God Through Pain and Suffering:
Today, when you read books or websites on overcoming anxiety and handling fear, they usually talk about removing thoughts. They say: Do not think about that; do not think those negative thoughts. Control your thoughts, expel the negative ones. But here we see the peace of God is not the absence of negative thoughts, it is the presence of God himself. “The God of peace will be with you” (Phil 4:9).
Christian peace does not start with the ousting of negative thinking. If you do that, you may simply be refusing to face how bad things are. That is one way to calm yourself–by refusing to admit the facts. But it will be a short-lived peace! Christian peace doesn’t start that way. It is not that you stop facing the facts, but you get a living power that comes into your life and enables you to face those realities, something that lifts you up over and through them.
Many believers have experienced this peace of God. It is not just positive thinking or willpower. It is a sense that no matter what happens, everything will ultimately be all right, even though it may not be at all right at the moment. In my experience, people usually break through to this kind of peace only in tragic situations, often in the valley of the shadow of death. Here is a metaphor for it. If you have ever been on a coast in a storm and seen the waves come in and hit the rocks, sometimes the waves are so large that they cover a particular rock, and you think, ‘That is the end of that rock.’ But when the waves recede, there it is still. It hasn’t budged an inch. A person who feels the ‘peace that passes understanding; is like that. No matter what is thrown at you, you know it will not make you lose your footing. Paul of course is the classic example. He is beaten; he is stoned; he is flogged; he is shipwrecked; he is betrayed; his enemies are trying to kill him. There is wave after wave, and yet–there he is still. ‘I have found a way to be completely poised under any and all circumstances,’ he said. All the waves of life could not break him. And he says it isn’t a natural talent of his–you and I can learn this.
That is the character of Christian peace. It is an inner calm and equilibrium but also a sense of God’s presence and an almost reason-transcending sense of his protection.