Michael Horton's new book "The Gospel Commission: Recovering God's Strategy for Making Disciples" is an excellent book on the Great Commission and it's implication in a number of areas. I think it would be a book worth your time and reading.
It is a mix of covenant/Reformed theology and missional theology. It has three sections. It lays out the strength that Jesus has in the "all authority" of the Great Commission. He makes a number of references to Christopher Wright's the Mission of God.
He takes on a couple issues: (1) that pitting Jesus & the kingdom vs. Paul and the gospel. He states clearly the kingdom is the gospel and the gospel is the kingdom. Part 2 is the Mission Statement and Part 3 is the Strategic Plan.
The book is not so much an exegetical treatment of the kingdom's unfolding, although it is clearly grounded in that. Rather the book covers those practical issues of the kingdom as it relates to the Great Commission. On important area is the current discussion about the role of mercy ministries and the role of Christians in culture. I believe Horton's book charts an excellent pathway through the issues. What he says briefly about politics is helpful.
(2) He distinguishes between the church its mission as the church (organization) vs. the Christian and their calling as Christians with differing vocations. So in my mind one of the weaknesses of the missional and kingdom approach is that so often we are told that mercy ministry is doing the kingdom and this can come at the expense of preaching the gospel (none of us would hold that, but it is out there)-- Horton gets beyond this by returning to a two kingdom doctrine--that we can be called to go out into the world and be salt.
Horton does discuss briefly the role of the diaconate--but not to the extent that Tim Keller deals with it in say his Ministries of Mercy.
One thing notable Horton writes: "We often seem more eager to say that the early Christians weren't communists than we are to say what these texts clearly affirm: namely, that in a real sense, giving to the needs of the poor among us is not charity but justice--not the justice that is appropriate for the kingdom of this age, but the justice that can only be a foretaste of the age of come." (p222).
It is a very helpful book in terms of theory, it also gets into some issues of practice by arguing that the church's main focus is on preaching, sacraments and making disciples. So rather than expanding the church's mission to include ever social issue, he limits the role of the church but then argues the church equips Christians to be Christians and that entails each having their own vocations in the world. So he is real clear about the church not becoming beholden to political agendas on the left and the right but Christians living out their convictions can work in the sphere of common grace. Horton argues that if the church focuses on its mission as the church the people will be equips for their vocations but the church should not as the church take up every vocation. Distraction from its mission has led evangelicalism to the fiasco it is in today--little Bible knowledge and Therapeutic Moralist Deism--or 'Christless Christianity'.
The book ends with a defense of Biblical spirituality. He points to an ironic inconsistency in the emerging church that it is against escapism but it finds inner renewal spirituality compelling. He also points out the difference between living the gospel vs. proclaiming the gospel.
One cannot read this book without being impressed by the Biblical exegesis that informs Horton's work and the wide scope of his reading and citation of sources from liberal theologians, emerging church writers, Biblical studies scholarship, etc. This is classic of all of Horton's work, particularly his 4 volume academic series in theology. But this book is pastoral in its heart taking on issues for the sake of church practice.
Not everyone will agree with all of the applications of Horton's Two Kingdom approach but in general they path he charts does seek to guard us from over-realizing the present position of the Christian and NT eschatology. This book will challenge your thinking and provides a healthy balance in responding to the issues of the day while fairly representing them. Those who are involved in the missional church should read this. Those concerned with the Kingdom of God should read this book for its implications in the church. Those concerned to see Christians engage the culture should read this book so that they understand the nature of their task.