Abstract
John Flett's proposal for a trinitarian understanding of the missio Dei that is rooted in the undivided being and act of God requires not only a theology of the church that cannot separate God's mission from the church's existence and purpose; it calls for a re-casting of the theological disciplines for the sake of missional formation of church leaders. For doctrinal and systematic theology, this would entail re-thinking the Nicene marks of the church. As a further step, Karl Barth's missional exposition of the gospel of reconciliation could prove to be the effective corrective to the missional reductionism of Western ecclesiologies.