Duplex Regnum Christi: Christ’s Twofold Kingdom in Reformed Theology, by Jonathon D. Beeke, vol. 40, Studies in Reformed Theology. Leiden: Brill, 2021, xiii + 255 pages, $62.09, paper.

“Two-kingdom” theology has become a vexed question in contemporary Reformed circles. The issues usually press upon the proper understanding of the relationship between the church and state, and both in relation to God’s law, enveloping vexed questions about the nature of natural law. Frequently in discussions over two kingdom theology, authors appeal to historical precedents in Protestant churches, aiming at systematic formulations. Targeting historical developments rather than contemporary questions, Jonathon Beeke explores Christ’s twofold reign in sixteenth and seventeenth century contexts, seeking to understand his chosen authors on their own terms and in their own times rather than in light of contemporary debates (12). His valuable research presses modern readers to step back for a moment to listen to the voices of older authors from different times and places. Doing so often places different options on the table than what we find in modern discussions, enabling readers to take stock as they often claim to be close or far away from historic Protestantism (14). Ultimately, he argues well that Reformed orthodoxy opted to refer to Christ’s twofold kingdom, essentially as God and economically as God incarnate, rather than two distinct kingdoms. This has potential to alter the direction of current debates, at least to an extent.

Beeke’s aim in this work is to investigate what select early modern Reformed authors taught about Christ’s twofold reign, and why they did so (14). His thesis is that Reformed orthodox portrayals of the duplex regnum Christi stood in basic continuity with early Reformed formulations, with some significant developments (19, 215). Following a general introduction and statement of his argument, Beeke surveys patristic and medieval foundations for the twofold reign of Christ in chapter two. This sets the stage for his treatment of Luther in chapter three, completing his overview of the Reformation period with Bucer and Calvin in chapter 4. Chapter 5 marks a shift towards Reformed orthodoxy as his main target by highlighting key terms and ideas related to the question. This paves the way for chapters 6 through 8, focusing on Reformed scholastic university instruction at Leiden, Geneva, and Edinburgh, as each illustrates Reformed views of Christ’s twofold reign in varying contexts. Beeke takes readers off the beaten path of treating familiar authors, doing groundbreaking research on figures such as Franciscus Junius, Johannes Scharpius, and David Dickson. Chapter 9 concludes the work via restatement, summary, and assessment of the whole. From the outset, Beeke notes that “two kingdom theology” is actually an anachronistic term, likely stemming from Karl Barth’s description of Lutheranism in 1922. He retains the language, partly due to its prevalence in secondary literature (2), noting as well that for early modern Reformed authors, church-state relationships became a secondary issue when establishing Christ’s twofold reign (13). The main concerns related to this doctrine in Reformed thinking were Christological and covenantal, saying more about Christ’s pre and post-incarnate states and what implications this had for our relation to him. The fact that Beeke draws similar evidence from Leiden, Geneva, and Scotland, among other sources, illustrates that stressing Christ’s single reign with general and mediatorial aspects was shaped more by the trajectory of Reformed thought than by local and national contexts (216). The result is a clear and broad characterization of the Reformed tradition on this point, which holds great promise for further research.

While several features of this work stand out as particularly clear, shedding light on much recent debate, two stand out. First, Beeke’s contrast between the Lutheran two kingdoms teaching and the Reformed conception of Christ’s twofold kingdom is a substantial dividing point that should shape any contemporary discussion. “Two-kingdoms” ideology aimed to explain the different responsibilities of magistrates and ministers while Christ’s twofold kingdom aimed to press people’s relationship to Christ as both Creator or Redeemer. Second, he shows the development of Christ’s twofold kingdom in Reformed thought, especially in light of Christology and covenant theology. Specifically, the connections he makes between Turretin’s treatment of the covenants of nature and of grace, with Christ’s twofold reign as Creator and Redeemer, breaks new ground (169) and sheds light on the crux of the matter. The primary issues are not thus church and state relationships as much as who Christ is and how people relate to him.

Though the author asserts repeatedly that church/state relationships were not in view primarily under the idea of a twofold reign of Christ, one essential and eternal, the other mediatorial and (maybe) temporary (e.g., 118), the distinction and relation of powers in the church and state remains a natural ancillary discussion. Christ governs the world essentially as God, and world government should respect his law as the eternal Son of God. Christ then rules over the world for the sake of the church as Mediator, with a special aim towards the redemption of the elect and the transformation of heaven and earth.

Surely this distinction still results in different ways in which the state and the church relate to God’s law, as it did in James Bannerman’s Church of Christ, for instance. Reformed orthodoxy may present a twofold kingdom of one Christ rather than two kingdoms, yet Christ’s twofold reign is a Christological issue with important implications for church/state relations. All people are subject to law under Christ as Creator, and he reigns over all as Mediator calling people to repentance and faith. However, it remains striking, as the author notes, that Reformed treatments of Christ’s twofold reign appeared in Christologically grounded theological loci and not in relation to pastors and magistrates (148–49). The larger picture that emerges is that Christ’s twofold reign was primarily a Christological issue, with implications for the distinction of power in church and state. This overlap of issues appears more readily in authors like Turretin, as Beeke acknowledges (e.g., 165), but the connection between Christ’s twofold kingdom and church-state relationships remains a natural one. Keeping this caveat in mind, Beeke rightly observes that confusion often results from the fact that people treat the scope of Christ’s mediatorial kingdom as narrower than that of his universal kingdom as Creator while in classic Reformed thought the scope of two aspects of Christ’s reign remained universal, though with differing aims and relations (e.g., 21, 114, 224). This point can help alleviate some confusion and charges of inconsistency among Reformed authors as they come to bear on modern debates.

Historical theology cannot tell the church what to believe, but it can tell us what the church has believed. It is vital to hear historical people with their own accents in their own contexts without running into the danger of seeing our own reflections in their viewpoints. This is precisely why historical studies like this one can help modern theological debates, giving us other ideas to evaluate and making some lines in the sand clearer (12). Beeke’s book, as an exemplary model of historical theology, thus contributing something vital to ongoing discussions of two kingdoms theology today, pressing towards sound historical exegesis rather than mere theological eisegesis. Not all will be satisfied with his conclusions, but that is part of the beauty of historical theology. Readers are not obligated to like what they find, even as they seek to learn from what they find. I cannot commend this book highly enough, both in relation to the history of Reformed thought and for its potential to clarify contemporary discussions.

Ryan M. McGraw is a minister in the Orthodox Presbyterian Church serving as a professor of systematic theology at Greenville Presbyterian Theological Seminary in Greenville, South Carolina. Ordained Servant Online, January 2022.