As long as my sense of being valuable and significant is tied to my success, it will be a fragile thing. But when I come to know in the marrow of my bones that I am just as valued and loved by God when I have fallen flat on my face, then I am gripped by a love stronger than success or failure . . .
When you have a discouraging spirit or train of thought in your mind, you can be sure it is not from God. He sometimes brings pain to his children - conviction over sin, or repentance over fallenness, or challenges that scare us, or visions of his holiness that overwhelm us. But God never brings discouragement. Always, his guidance leads to motivation and life.
-John Ortberg in If You Want to Walk on Water, You've Got to Get Out of the Boat, page 143.