David VanDrunen’s Natural Law: A Short Companion is a concise yet theologically rich introduction to the concept and function of natural law, written in a style accessible to both students and informed lay readers. For those newly curious about the resurgence of Protestant interest in natural law over the past two decades, this book serves as an ideal entry point. For more seasoned readers, it offers a distilled presentation of VanDrunen’s broader body of work—including Natural Law and the Two Kingdoms: A Study in the Development of Reformed Social Thought (Grand Rapids: Eerdmans, 2009), Divine Covenants and Moral Order: A Biblical Theology of Natural Law (Grand Rapids: Eerdmans, 2014), Politics After Christendom: Political Theology in a Fractured World (Grand Rapids: Zondervan, 2020), and the more popular Living in God’s Two Kingdoms: A Biblical Vision for Christianity and Culture (Wheaton, IL: Crossway, 2010)—highlighting the least controversial and most foundational aspects of his argumentation.

VanDrunen’s signature clarity and organization are evident from the outset. In the opening chapter, he succinctly defines natural law as “the law of God made known in the created order, which all human beings know through their physical senses, intellect, and conscience, although they sinfully resist this knowledge to various degrees” (p. 1). He carefully distinguishes natural law from two related concepts. First, unlike “natural revelation,” which encompasses God’s revelation of both himself and his moral will, natural law pertains exclusively to the latter (p. 8). Second, he differentiates it from “natural law theory,” which refers to human reflection upon the content of natural law. In contrast, natural law itself is not synonymous with human reason but is best understood as divine revelation. VanDrunen argues that this interpretation aligns more closely not only with the actual writings of Thomas Aquinas but also with the dominant understanding of the early Protestant Reformers, including Luther, Calvin, and their successor, Francis Turretin (pp. 10–14).

Chapters 2–4 then establish biblical support for this conception of natural law as inherited by the Reformers. Chapter 2 explores the created order, the imago Dei, the Noahic covenant in Genesis 9, and the teaching of Proverbs and the prophets. VanDrunen emphasizes that God created a world filled with “meaning, purpose, and order” (p. 30) and that humans, made in God’s image, are called to discern and live in accordance with this moral structure (p. 23). While modern and postmodern thought often denies the possibility of moving from “is” to “ought,” Scripture affirms that this capacity is inherent in humanity, though impaired—not obliterated—by sin (pp. 25–27).

Chapter 3 expands the argument by examining scriptural evidence that all people, not just members of God’s covenant community, possess some awareness of divine moral demands. These include a general sense that “there is a God who should be feared” and that there are certain “things that ought not to be done.” Chapter 4 grounds divine judgment in natural law, citing both Old Testament prophetic oracles and New Testament texts like Romans 1–2. Such passages condemn both the denial of God’s existence (hubris) and the rejection of God’s moral standards (injustice). The chapter concludes by outlining ways in which natural law serves as a foundation for the gospel.

The final two chapters shift from theological exposition to practical application. Chapter 5 explains how natural law functions in daily Christian life. It is especially necessary, VanDrunen argues, because Scripture does not address every moral scenario in explicit detail (p. 82). Moreover, natural law elucidates why certain behaviors are forbidden: they contradict the moral grain of the created order. The Proverbs, though not exhaustive, instruct readers in acquiring this moral discernment. When we act contrary to this order, we are not merely wrong but also “stupid” and “destructive,” living against the grain of divine design (p. 85). VanDrunen also contends that natural law is more immediately applicable to contemporary moral reasoning than the Mosaic law. When questioned about divorce, for example, Jesus “pointed his Jewish listeners not beyond the Mosaic law to its fulfillment in him but before the Mosaic law to what God did in creation” (p. 93).

Chapter 6 addresses the use of natural law in the public square. VanDrunen observes that “people learn the natural law in much the same way that they mature in wisdom,” through prolonged habituation and instruction by the morally wise (p. 101). This leads him to minimize the role of sophisticated argumentation, and he also cautions against both “naïve optimism” and “nihilistic pessimism” in public discourse—expecting too much or too little from natural law persuasion. He concludes with three prudent strategies: Christians should promote humility, appeal to shared moral intuitions among fellow citizens, and use empirical evidence judiciously, lest it inadvertently undermine otherwise sound moral arguments (pp. 113–17).

As the resurgence in Protestant natural law thinking continues, this book will not only be useful to new students but also as a helpful summary on many points of present Protestant consensus. It also indicates important questions for those seeking to carry the conversation forward. How should we conceive and speak of the relationship between acquired and infused virtue touched on in the discussion of the natural law’s habituation? What is the role of formal church authority in relation to acquired virtue, and, related to this, what are the boundaries, if any, for the church when speaking authoritatively on matters drawn from natural law rather than Scripture? Are other frameworks more promising for resolving such matters? An introductory volume should not be expected to address the details of such complex questions, however, and this book will serve as an excellent guide to the contours of their foundations.