Open up another chapter in the book and read 'gain
It could be understood as:
1) Look to the future but remember your past mistakes so that they don’t happen again.
2) Get a fresh start and look at ways to gain something, whether it’s money, peace of mind, or just something better.
3) Throughout this song he is sorta like a storyteller for himself. He’s the main character and the narrator. He is opening another chapter in his life now, after he has told you how he got to where he is at at this point in the story.
4) Open up the Bible and read it again and reexamine your life.
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