This book explores the theme of the missional conversion of the church, namely how the church is transformed toward its missionary vocation, from a biblical-theological perspective. The purpose of this book is to find biblically grounded, theologically sound, and practically applicable principles helpful for the church which seeks to be continuously shaped into a missional community which authentically and fully participates in God's mission today. The biblical-theological findings on how the triune God in the biblical narrative shapes the people of God toward their missionary vocation demonstrates, first, that, in Scripture, the missional conversion of the church is primarily the consequence of its continuous encounter with the triune God, and, second, that this divine-human encounter for the missional conversion of the church is ineluctable in view of the ongoing tension between the missional faithfulness of God in fulfilling the missionary vocation of the church, on the one hand, and the missional failure of the church in its missionary vocation, on the other hand.