There is a difference in tone between the nines. That pithy little phrase will keep you focused as you read through the chapter, so you don't lose sight of the theme. So you must accept your limitations yet learn to transcend them. Here you thought you were just playing a round of golf, when all the while you were practicing a higher spiritual discipline. In his footnotes, Peck throws in little side stories that further explain his point.
Illustrations appear throughout the book that diagram the various imaginary holes.
He writes this so a person who has never even heard of the game could follow what is happening. He does a good job of it keeping it interesting even if you are already familiar with the sport. He has a few terms that recur throughout the book. On the golf course your toughest opponent can be none other than yourself. Another term is cathexis, or attachment.