In this book, Emmanuel Mbennah argues that Christian spiritual maturity is the bridge between the new identity of the Christian, articulated in Ephesians 1-3, and the moral code of the Christian life commensurate with the new identity, presented in Ephesians 4:17--6:20. From an interpretation of Ephesians 4:13, Mbennah brings to the fore what Christian spiritual maturity is and why it is imperative. He argues that Ephesians 4:1-16 is about spiritual maturity, and not about Christian unity, except unity as a by-product of maturity. A case study in which the meaning of spiritual maturity is used as a critical standard to evaluate the spiritual maturity of a church in a particular context further clarifies the meaning of spiritual maturity and demonstrates what a sad state of immaturity a church could be in. Mbennah calls for the Church's return to the pursuit of maturity and a return to the subject in New Testament scholarship.