Since at least the 1950s, historians of the Protestant Reformation and scholars of divinity have debated the nature and the significance of covenant theology and how it contributed to confessional differences in the sixteenth and seventeenth centuries. The debates occur along two main axes. The first is whether early modern theologians believed the Abrahamic covenant between God and humanity revealed in the Old Testament endured and was simply renewed through Jesus's sacrifice on the cross, or whether that sacrifice replaced the old covenant with a new, essentially different one. Modern scholars often refer to the belief that the old and the new covenants were one and the same as the unity of the covenant or the testaments. The second axis is about the nature of the covenant with Christians: whether it is unilateral or bilateral, a one-way promise from God or a mutual agreement under which humans are obliged to respond in some way to keep their end of the bargain. The general consensus is that for Martin Luther, the old and new covenants were not the same and that the Abrahamic covenant was bilateral, but the new covenant for Christians was unilateral. Where things get interesting—and where the vast majority of the scholarly debate on this issue lies—is in figuring out what theologians in the Reformed tradition (later known to many as Calvinist) espoused on this issue. Most scholars agree that Huldrych Zwingli, Heinrich Bullinger, John Calvin, and others in the Swiss Reformed tradition upheld the unity of the covenant, but they disagree on their views of the unilateral or bilateral nature of that covenant. This has obvious implications for soteriology: asserting that humans have to perform any action or duty to uphold a reciprocal agreement with God appears to challenge the Reformation doctrines of sola fide and sola gratia, justification by faith and grace alone.

The latest contribution to this debate is Robert Wainwright's Early Reformation Covenant Theology: English Reception of Swiss Reformed Thought, 1520–1555, a revised version of a doctoral dissertation completed at Oxford University in 2011. Wainwright argues that Zwingli, Bullinger, and Calvin all believed in a unified, bilateral covenant extending from the Old Testament to their own times, and that this belief deeply affected their theologies, especially their views of the sacraments. He explains that this did not weaken their commitment to sola gratia because grace, works, and sola scriptura were intimately tied together, “delicately balanced,” and not yet formally defined as they would become later in the sixteenth century under Reformed federal theology (344). Moreover, through the examination of writings by four English theologians, he asserts that three of them—William Tyndale, Miles Coverdale, and John Hooper—also upheld a unified, bilateral covenant and that this demonstrates the impact of early Swiss Reformed theology in England. The writings of the other Englishman, John Bradford, do not demonstrate the development of the same covenant theology, but this confirms the overall argument because there is less evidence that Bradford was influenced by the Swiss theologians. These conclusions are important, according to Wainwright, because they challenge previous scholarship and common assumptions about the insular and exceptional nature of the English Reformation and demonstrate a transitional phase between the soteriology of late medieval theologians and the formalism of later sixteenth-century Protestant theologians. He asserts that “Reformed theologians were able to hold together salvation sola gratia and the requirement for godliness without resorting to Luther's radical solifidianism to maintain the distinction. They were as comfortable as their [medieval] predecessors had been with seamless conceptual links between righteousness, faith, and sanctification under the auspices of covenant relationship according to the law of love” (20).

Early Reformation Covenant Theology has strengths and weaknesses. Wainwright's research into the primary sources is solid. His theological analysis is reasonable, although there will certainly be other historical theologians who disagree with some of Wainwright's interpretations. It is true, as he points out in the introduction, that no previous scholar has done a systematic analysis of English covenant theology in the first half of the sixteenth century, and so Wainwright does contribute to the long-standing debates about the significance of the covenant in Reformation theology and the relationship between Protestantism on the European mainland and in England. Nevertheless, Wainwright exaggerates the originality of the contribution in some ways, and the book could have been significantly shortened and still communicated its main points. For example, chapter 2, “Reformed Theology in England,” which is seventy pages long, is largely a synthesis of previous scholarship about the personal and intellectual connections between Switzerland and England between 1520 and 1555. It provides a background to Wainwright's own theological analysis, but it could have been much shorter and absorbed into the introduction. More importantly, it demonstrates that Wainwright's assertation that there is an urgent need to correct previous historians’ assertions of the “insularity” (22) and “exceptional” (24) nature of the English Reformation is not true anymore, though it may have been when his research for the dissertation began over ten years ago. By now, most experts agree that English Protestantism was influenced early on by ideas from the mainland, including Swiss Reformed theology. (See, for example, Peter Marshall's 2017 Heretics and Believers: A History of the English Reformation and Diarmaid MacCulloch's 2018 biography of Thomas Cromwell.) Finally, there is the problem that covenant theology is particularly elusive and difficult to prove one way or another, as we see in the fact that historians and theologians have been arguing about it for decades. It can appear at times as if whether or not a theologian's idea of the covenant was unilateral or bilateral depends on which sources are chosen as evidence and on small, technical interpretations of language that are beyond the intellectual capacity of the average reader. This book will mostly be of interest to narrow specialists in the field, but the arguments are intriguing and will likely stimulate more debate.