Here’s a brand-new theological book that I recommend: Augustine, the Trinity, and the Church: A Reading of the Anti-Donatist Sermons by Adam Ployd of Eden Theological Seminary. In this book, the author gives us a compelling reading and analysis of Augustine’s forty-one interrelated sermons, delivered in December 406 through mid-summer 407, most of which concern that break-off group of North African Christians who preached the necessity of the moral purity of the church and, thus, who believed that the sacraments’ effectiveness rely upon the minister’s character.
As Dr. Ployd shows, Augustine’s sermons have a purpose of community- and faith-building, via the way Augustine connects his ecclesiology and his Trinitarian theology. According to early reviews of the book, scholars of Augustine have rarely treated his theology of Trinity and of Church together. But Augustine's theology of God's love, the body of Christ, the work of the Holy Spirit, and the unity of Baptism work together in this sermons series. He writes, “Throughout [Augustine’s] sermon series, he ….defend[s] a pro-Nicene understanding of Christ and the Trinity... [and] uses pro-Nicene principles and exegesis to construct his anti-Donatist vision of the church, and in doing so, he describes how the church shares in the life of the Trinity through the Son’s giving of the Spirit to his own body. The unity of the church is an expression of the unity with which the Trinity operates to establish that church” (p. 3). In his historical and theological analysis of the sermons, Ployd points to ways Augustine speaks to today's church, flawed and infuriating as it is, but ever sustained by Christ.
Augustine, the Trinity, and the Church is published by Oxford University Press (July, 2015) as part of the Oxford Studies in Historical Theology. I'm an adjunct teacher at Eden Seminary and know the author.