This paper explores the frames of ecclesiology through a missiological lens and to propose that church becomes the church as it joins Christ in his mission. The first frame considers the Trinity, God, and his mission. The next frame surveys the grand theme of mission in the scriptures. With the last frame exploring the church in mission; concluding with a New Testament model. The goal of this paper is twofold in showing that mission rightly proceeds ecclesiology as it produces the essence of ekklesia and testimony of how knowledge of this is making a difference in a local church. 
The term “missional” was devised to reflect the understanding that mission is not merely a sub-category of ecclesiology, but belongs to the essence of what it means to be the Church. The Church does not “do” mission; rather, the Church “is” mission.  The church cannot be the church apart from missions, but the church must become a “living hermeneutic of the gospel before God.”  Missional ecclesiology necessitates more of the church than determining which neighborhood service projects to engage in or defining what congregational emphasis will draw people to the pews. Missional ecclesiology is a way of understanding the church and its original ethos as “sending and being sent.” In missional ecclesiology, the Church is not a building or an establishment, but a fellowship of witnesses, equipped and empowered by God, to send and be sent into the world, participating in Christ’s work. Missions is not a program of the Church; instead, the mission of God creates the Church and the church becomes itself as it joins the Lord’s mission.
Missio Dei is a Latin phrase that interpreted means, "Mission of God."  Missio Dei’s foundation rests upon the example of God’s own “self-sending” in Christ by the Spirit to redeem His creation.  The term missio Dei can be traced back to Augustine.  Also, it was Thomas Aquinas who first coined the term to explain the quest of the Trinity; the Father sending the Son and the Son sending the Spirit.  Karl Barth wrote a paper in 1932 that set out the idea that mission was God’s work, and that official church mission was an obligatory answer to God’s missio call. Karl Hartenstein adopted this concept, who then applied the term missio Dei to differentiate it from the missio ecclesiae; or the mission of the church. It was at the 1952 Willingen meeting of the International Missionary Council that Hartenstein further clarified the theological concept of missio Dei. Ironically, the Willingen meeting did not include missio Dei. Hartenstein used it in his noted review of the convention.  
Arthur Glasser later connects mission Dei with the sending nature of God and the whole of redemptive history. In this sense, the whole of redemptive history is a history of Missio Dei—God’s redemptive purpose for the nations. It follows then that the goal of Missio Dei is to incorporate people into the Kingdom of God and to involve them in his mission. Because the Father is the Sender, Jesus Christ the One who is sent, and the Holy Spirit the Revealer, it follows that noninvolvement in mission on the part of the church is to be deplored. 
