Webber, a man who slowly learns that change is the nature of the world. As such, the phrase shared with him by a local civic leader "don't you know you can't go home again" becomes his philosophy by the end of the book. George was a writer who peeled back the layers of his town for the world to see. After his book is published there are death threats and he realized that going home is not a good idea. In the middle of this the stock market crashes (the book is set in the late 1920's and 1930's) and the world as America knows it has changed. Forever changed by events George begins to repeat the phrase spoken to him "doesn't he know, he can't go home again."
Some believe these words echo the words of Jesus "Only in his hometown, among his relatives and in his own house is a prophet without honor."
The phrase for me really comes down to two big lessons.
#1 Change is inevitable. It occurs. It happens. Going back to the way things were is not possible in the midst of a huge crisis.
#2 We sometimes idealize the past when we should be enjoying the present.
The nature of the world is change. Are you swimming against the times? Are you floating along?
There are some things worth fighting for and yet, many of us are so busy and tired from fighting the wrong battles that when the ones worth fighting for arise, we are too tired.
Go in peace and go with God.