When we are in a negative frame of mind, it is only natural to doubt rather than to believe. From a Buddhist point of view, doubt is a sign of a lack of complete understanding and a lack of spiritual education, but it is also seen as a catalyst in the maturing of faith. It is when we face doubts and difficulties that we discover whether our faith is a simplistic, pious, and conceptual one, or whether it is strong, enduring, and anchored in a deep understanding in the heart. If you have faith, sooner or later it may well be put to the test, and wherever the challenge may come from - from within you or from outside - it is simply part of the process of faith and doubt. ~Sogyal Rinpoche