Here are a couple of blurbs:
This is an important book on a neglected subject! Erik Thoennes shows that God is pleased with those today who, like Phineas, David, Paul, and Jesus himself, are jealous for the honor of our great God in an age that increasingly disregards him and his commands. Carefully researched and clearly written, this book shows that there is a good kind of godly jealousy which will give background and courage to our Christian lives.
--Wayne Grudem
Because the virtues are mutually reinforcing and require the presence of other virtues to be developed fully, a life of character will remain elusive if a particular virtue is disregarded. Today, jealousy has a public relations problem: It is widely misunderstood and regarded as a vice. In this scholarly yet accessible book, professor Thoennes fills a huge void regarding godly jealousy. With skill and admirable familiarity with the relevant literature, he restores godly jealousy to its proper place in a life well lived. Those concerned about character development cannot afford to neglect this book.
--J. P. Moreland