Screwtape, an upper-level demon, writing to his trainee Wormwood:
[God] relies on the troughs even more than the peaks; some of His special favourites have gone through longer and deeper troughs than anyone else … He leaves the creature to stand up on its own legs — to carry out from the will alone duties which have lost all relish. It is during such trough periods, much more than during the peak periods, that it is growing into the sort of creature He wants it to be. … He wants them to learn to walk and must therefore take away His hand; and if only the will to walk is really there He is pleased even with their stumbles.
- C.S. Lewis, Screwtape Letters