I think the question “Why should I do right?” (or perhaps “What is the best motivation to to right?”) is one of the most important questions we can ask in our process of sanctification. The opening verses of 1 Cor 13 should be enough to convince us of that. And I’m convinced that most Christians haven’t come to a rigorously scriptural answer. Why should I do right? “Because God says so” is not enough—at least God doesn’t think so. He offers reasons.
I haven’t read this book, but from what I know of Edwards on this topic (and from the blurbs the author got), it promises to be helpful.