Let the Nations Be Glad by John Piper is a MUST read for any Christian. In fact, i would recommend it to any non-believer who has ever wondered what it means to be a Christian. With so many poor example of the Christian faith this book opens our eyes to the core of Christian belief and mission.
Piper is known for his strong Biblical views - especially regarding suffering and Godward focus. Even if you are not a Piper fan you can embrace the need to swing the pendulum of American Christianity from our focus on self-help to a more missional mindset.
Early in the book Piper delivers the quote, "Missions exists because worship doesn't." He points to the "chief end of man" which is to "glorify God and enjoy Him forever" as expressed in the Westminster Shorter Catechism. The goal of glorifying of God in and through every person motivates the need for missions. Our driving force should be to take the message of the gospel to the world so that people of all kinds might worship their Creator and Savior.
I urge you to read this book and be challenged. As always, I hope it makes sense! AS