While a body that has been nourished too well and has received too much rest gives man a false notion of fullness and autonomy, introducing pride in him, asceticism weakens man’s body and thus causes him to sense his real fragility, the weakness of his present nature, the ephemeral character of his bodily and earthly existence, the relativity of his being. This labor thus leads him to humility. As St Isaac observes: “The more sufferings increase, the more sufficiency diminishes.”
~Dr Jean-Claude Larchet (Therapy of Spiritual Illnesses, vol.2 p.270)
Prayerful Life 