John Ortberg, Faith & Doubt, 74:
If I leap, if I trust, I do not know for sure what will happen.
What I do know is this: if I don’t leap, if I don’t trust, if I don’t hope, if I don’t ask, I will never soar. I will never know. I will live and grow old and die standing on the side of that cliff.
Note: not to be taken literally.