To consider illness strictly as a phenomenon unto itself is almost inevitably to see it in a negative, sterile light; and this only increases the physical suffering and moral pain which result from a sense of its absurdity. The consequence of such an attitude is generally to leave the way open to the activity of demons and to develop in the soul troubling passions, such as fear, anxiety, anger, weariness, revolt, and despair. These states not only do not relieve the body, they most often increase the symptoms of the evil that affects it, thereby creating sickness even in the soul. The illness then serves no good at all, but it becomes for the ill person a source of spiritual deterioration which puts his soul in jeopardy perhaps more than it does his body.

It is because of this very danger that the Fathers stress the point that “it is not in vain, nor without reason, that we are subject to illnesses.” This is why they encourage us to be vigilant when illness strikes, and not to trouble ourselves first of all with their natural causes and means to cure them. Rather, our first concern should be to discern their meaning within the framework of our relationship to God, and to throw light on the positive function they can have in furthering our salvation.

—Jean-Claude Larchet, The Theology of Illness