From the viewpoint of BELIEFS all doubts are disastrous. From the viewpoint of FAITH, doubt is the indispensable stimulant. To lose one's BELIEFS may not be a loss but a gain: an opportunity. "When the heart weeps for what it has lost, the spirit laughs for what it has gained," is an ancient Sufi saying. To lose one's FAITH, however, is catastrophic; the loss of this vital human constituent means mutilation, dehumanization, cynicism, nihilism.
To interpenetrate an entire human life with divine life, it is not enough to kneel once a year in front of the crib and let oneself be moved by the charm of the holy night. One needs to live one's entire life in daily communication with God, to listen to the words that God has spoken and that have been transmitted to us, and to follow these words.