From the Preface:

I’m publishing this book as one small contribution to the building up of believers in the Lord Jesus Christ. The final motivating factor that pushed me to start writing it was my teaching a substantial Bible study with a group of brethren whom I had known long enough to become friends with. Using my long efforts of studying Scripture, I taught a series on the nature of the Lord’s church, and on the New Testament teaching of discipleship. I’ve long had a desire to teach on this topic, since it’s an urgent need in western Christianity. And now I’ve been persuaded that it’s time to share this teaching in book form with a larger audience of brethren – and possibly unbelievers – on the Internet, and in print. The teaching in this book is needed, urgent, and life-changing. Please read this book prayerfully and carefully, and test everything I say with the teaching of our Lord and the New Testament authors. I pray the Lord uses it to teach you more about who He is, what He’s done, and what He’s doing, so that you will see much more of why He’s so worthy of love, worship, and imitation.

The Kindle edition is now available, and a paperback one will come soon. Here’s a preview and link to buy it: