I love this story about holiness near the end of the book.
It seems that a young aspirant to holiness once came to visit the hermitage of an old holy man who was sitting in the doorway of his quarters at sunset. The old man's dog stretched out across the threshold as the young spiritual seeker presented his problem to the holy man. "Why is it, Abba, that some who seek God come to the desert and are zealous in prayer but leave after a year or so, while others, like you, remain faithful to the quest for a lifetime?"
The old man smiled and replied "Let me tell you a story:
One day I was sitting here quietly in the sun with my dog. Suddenly a large white rabbit ran across in front of us. Well, my dog jumped up, barking loudly, and took off after that big rabbit. He chased the rabbit over the hills with a passion. Soon, other dogs joined him, attracted by his barking. What a sight it was, as the pack of dogs ran barking across the creeks, up stony embankments and through thickets and thorns! Gradually, however, one by one the other dogs dropped out of the pursuit, discouraged by the course and frustrated by the chase. Only my dog continued to hotly pursue the white rabbit.
In that story, young man, is the answer to your question."
The young man sat in confused silence. Finally, he said, "Abba, I don't understand. What is the connection between the rabbit chase and the quest for holiness?"
"You fail to understand," answered the old hermit, "because you failed to ask the obvious question. Why didn't the other dogs continue the chase? And the answer to that question is that they had not seen the rabbit. Unless you see your prey, the chase is just too difficult. You will lack the passion and determination necessary to perform all the hard work required by the discipline of your spiritual exercises."