In John's Gospel, the oneness of the Father and Son is described as the Father and Son being "in one another." Clive Bowsher's study shows that union with Christ in John's Gospel and letters is the in-one-another relationship of believers with the Father and Son by the Spirit—the intimate, loving, relational participation of the believer and God, each in the life, affections, ways, and work of the other. Insightful and accessible, Bowsher's study also explores connections with the shape of sonship, covenant and the life of the age to come. This volume fills a significant gap in the literature and promises to be a blessing to pastors, preachers, and scholars alike. Addressing key issues in biblical theology, the works comprising New Studies in Biblical Theology are creative attempts to help Christians better understand their Bibles. The NSBT series is edited by D. A. Carson, aiming to simultaneously instruct and to edify, to interact with current scholarship and to point the way ahead.