‘Usury is not Usury.’ The Early Dutch Reformed Theological Debate on Interest (and What Can be Learned from It)

Introduction

In 1637, at the height of the Dutch Republic's economic success, the Dutch Reformed preacher Johannes Cloppenburgh published a 170-page treatise on interest entitled Christian Instruction on Usury, Interest, Annuities, and All Kinds of Profits from Money with Money. First issued in the Dutch vernacular and later translated into Latin, ¹ the work defended the legitimacy of interest (hereafter: ‘usury’ ² ) on loans. Rejecting the traditional arguments against usurious lending advanced by medieval theologians and canonists, Cloppenburgh argued that usury was not only permissible in light of Scripture, natural law, and imperial legislation—it was appropriate. So long as one did not exact usury from the needy and the rate was moderate, the failure to compensate a lender for a loan would amount to an act of injustice and ingratitude. After all, why should a borrower who benefited from another's money or goods not allow the lender to share in that benefit? Unlike most scholastics, who relied on Aristotle in this regard, Cloppenburgh regarded money as a fruitful thing. When people's ‘ingenious use’ was applied to this instrument, money evidently ceased to be sterile. Hence, usury was reasonable. Not all usury was unlawful usury.

From an intellectual-historical perspective, Cloppenburgh's book marked a turning point. On the one hand, it looked back on a century of Reformed discussion of usury. As he suggested in the preface, a ‘general consensus’ had been reached among Reformed teachers, which he wished to make known to the wider world, and to ordinary people (idiotae, in the Latin translation) in particular. He accompanied the preface with a list of books and writings by Reformed theologians ‘who agree with us in principle regarding the doctrine of usury,’ ranging from Johannes Oecolampadius in the early sixteenth century to Johannes Wollebius in the early seventeenth. Since all but one of the works mentioned in this so-called Syllabus auctorum ὁμοψήφων were composed in Latin, Cloppenburgh decided to answer the call of the Synod of South Holland to produce a work of theological instruction for his unlearned compatriots. ³

On the other hand, Cloppenburgh's Christian Instruction marked a new phase in the history of usury doctrine. From the 1630s to the 1660s, the Dutch Republic witnessed a public debate among theologians and jurists over Lombards, or ‘table holders’ (trapezitae). ⁴ The point of contention was whether pawnbrokerage constituted an exploitative institution that ought to be prohibited by the public authorities, and whether pawnbrokers should be excluded from Holy Supper. Seeing it as its duty to uphold ecclesiastical discipline and combat widespread sins, the Synod of South Holland commissioned a work against the Lombards to be written by its chairman and secretary, Doctor Isaac Junius and Cloppenburgh, respectively. Since Junius was preoccupied with writing against another perceived threat, namely the Remonstrants, Cloppenburgh alone remained to pass judgment on the banck quaestie. His Christian Instruction concluded that Lombards who charged usury to the poor were guilty of a ‘crying sin,’ in violation of divine and natural law. Cloppenburgh's judgment, however, was not the final word on the matter: he soon found a worthy opponent in Claudius Salmasius, a staunch Calvinist defender of public moneylenders.

Specialised scholarly research on early Reformed or Calvinist thought about usury has been conducted for more than a century. An early and insightful study is that of the church historian Karl Holl from 1928. ⁵ Since this pioneering work, most attention has focused on the views of the founder of this tradition, John Calvin. The literature on his doctrine of usury is extensive. ⁶ A central question in this body of scholarship is to what extent the thinking of the Geneva Reformer represented a break with medieval conceptions. Several studies compare Calvin's ideas with those of Luther, Zwingli, and others. ⁷ Academic articles and book chapters have also been devoted to other sixteenth-century reformers within the Reformed tradition, such as Bullinger and Beza. ⁸ This topic is also frequently addressed in general surveys of their ethical or economic thought. As to the reception and influence of sixteenth-century Reformed positions, research has been done for seventeenth-century England and New England. ⁹

With regard to the Dutch Republic, where the Reformed Church was the official and privileged church, there exists a body of literature on the controversy over loan banks. ¹⁰ However, the earlier phase in Dutch Protestantism, which culminated in Cloppenburgh's treatise, has received very little scholarly attention. Existing literature on the development of economic thought in the Dutch Republic suggests that the discussion began with the jurist Hugo Grotius, whose views on usury were published in 1625, 1631, and 1641. According to the nineteenth-century German scholar Etienne Laspeyres, Grotius was ‘the first defender of taking usury on scientific grounds’ in the Dutch lands. ¹¹ This conclusion was uncritically repeated by later scholars, suggesting that Grotius had no predecessors. ¹² In reality, over twenty theological statements on usury—ranging from brief reflections framed by the Eighth Commandment (‘Thou shalt not steal’) to comprehensive accounts—were published from the late 1580s onward.

This article examines these early Dutch views in the context of the medieval usury debate and Reformed theological positions more generally. In addition to challenging Grotius's alleged primacy, I question the claim by historian Albert Hyma that, with regard to usury, ‘the Dutch Calvinists scrupulously followed Calvin throughout.’ ¹³ As is often the case, matters were more nuanced.

Selective History of a Thorny Question

Is it permissible to charge interest on a loan? The debate over ‘usury’ has a long history that far predates the rise of Christianity. There is no need to review that millennia-old story here. ¹⁴ What is relevant is the state of the debate from the scholastics of the High Middle Ages up to the sixteenth century, when the Reformers entered the scene. On the scholastic analysis of usury, there is a vast literature that cannot be fully surveyed here. We may, however, rely on John Noonan's authoritative study The Scholastic Analysis of Usury.

As Noonan explains in a chapter summarising the ‘Scholastic Theory of Usury, 1150–1450,’ there was no single scholastic theory. ¹⁵ Yet usury—traditionally defined as ‘whatever is added to the principal’ of a consumptive loan (mutuum)—was universally considered by theologians and canonists to be a sin against the rule of justice. In receiving more than what one gave, namely the principal plus usury, justice in exchange was violated. The arguments for this came from divine law and natural law: from Scripture, ¹⁶ the Church Fathers, and Church Councils on the one hand, and from natural reasoning or the agreement of the people on the other. While the act or intention of taking a profit on loans was prohibited, some writers allowed exceptions, as in cases of lending to the enemy or when the debtor made a spontaneous gift.

In the course of time, the scholastics began to allow for ‘interest’ (interesse, from quod interest, that which is between’ or ‘the difference’) on loans. Never to be sought for its own sake, interest was believed to be licit as a form of compensation. When a debtor failed to repay or return a loan on time, when a delay imposed costs on the lender, or when the lender faced missed opportunities due to the debtor's fault, he could claim compensatory interest. These so-called extrinsic titles to the law against usury—poena conventionalis, damnum emergens, and lucrum cessans, respectively—were eventually allowed only at the end of the loan term. The risk inherent in lending (periculum mutui) was not yet recognised as a title to interest.

It should be stressed that from the outset usurious loans were distinguished from commercial contracts. Indeed, one test of usury was whether it involved risk participation on the part of the lender. Business contracts other than loans that did involve such participation—such as the maritime loan (foenus nauticum) or partnership (societas)—were generally approved. The same was true of other financial arrangements, such as deposits (depositum), annuities (census), exchanges (cambium), and assurances (assecuratio), which were technically distinct from ordinary loans and therefore at most suspicious, not prohibited.

Between 1450 and 1750—a period presented by Noonan as one of criticism and revision—changing economic circumstances and new attitudes toward finance led to a further erosion of the prohibition on usury. While some scholars employ the language of ‘loopholes’ or ‘evasions,’ Noonan prefers to speak of areas of finance gradually being ‘removed’ or ‘cut away’ from the prohibition. Later, sixteenth-century scholastics from the School of Tübingen (Gabriel Biel, Conrad Summenhart, and John Eck), the Spanish School (Dominic Soto, Martin Azpilcueta ‘Navarrus,’ and Luis de Molina), and Leonard Lessius at Louvain all played their part in further liberalising the doctrine. Theological innovations included the wide acceptance of the triple contract (contractus trinus), which combined a contract of partnership with a contract of insurance; modifications to the conditions of the census contract; and the recognition of interest titles from the start of a loan. Lucrum cessans was increasingly accepted as a source of profit on a loan. Usury, however, was still formally banned, even though few formal arguments against it were left standing.

So much for five centuries of scholastic debate, the main lines of which the Protestants presented as ‘Catholic.’ How, then, did the Reformed themselves analyse the issue? As we have seen, Cloppenburgh believed that he stood within a tradition of like-minded Reformers. If so, they could be counted as supporters of his conviction that usury (which included interest) on ordinary loans was, in principle, acceptable, provided that a number of conditions were met: namely, that no usury was exacted from the poor; that the rate was reasonable and within the limits set by secular authorities; and that the transaction was (potentially) beneficial to both debtor and creditor.

His list of authorities consisted of first-generation Reformed theologians Johannes Oecolampadius, Martin Bucer, Philipp Melanchthon, Heinrich Bullinger, John Calvin, and Pierre Viret. These were followed by Girolamo Zanchi, Lambert Daneau, Daniel Toussain, François du Jon, and Wilhelm Zepper. Finally came Matthias Martinius, Bartholomaeus Keckermann, André Rivet, William Ames, and Johannes Wolleb from the third generation. Four of them taught at Dutch universities—Danaeus, Junius, Rivetus, and Amesius—the first three at Leiden and the latter at Franeker.

Cloppenburgh was fair enough to admit that there were exceptions. In the main text, he noted that not only the ‘hypocritical papist scholastics’ shared Aristotle's aversion to usury as a form of breeding money from money, but that ‘many godly and highly learned Reformed teachers’ did so as well. These could be found chiefly in England, siding with Johannes Luellus (John Jewell), but also in Switzerland, in the persons of Musculus and Benedictus Aretius. ¹⁷ However, the other party, to which he himself belonged, consisted of a ‘great many’ equally godly and pious theologians, as well as ‘famous’ legal scholars such as Carolus Molinaeus. The latter was born a Catholic, converted to Protestantism, and returned to Catholicism on his deathbed. His books—including the Tractatus commerciorum et usurarum, which approved of usury—were eventually placed on the Catholic Index of heretical works.

Of course, Cloppenburgh's classification was part of an argumentative strategy and should not be taken at face value. The fact is that there was no single Reformed position. Sixteenth-century Reformed theologians held differing views, each of which requires and deserves careful consideration.

With regard to Protestantism more broadly, the common opinion among nineteenth-century scholars was that Luther's attitude was conservative, if not reactionary; that of Melanchthon and Zwingli hardly more liberal; and that Calvin's was revisionist. Whereas Luther adhered to the canonist teachings that condemned usury, and Melanchthon and Zwingli were only slightly more lenient, Calvin was seen as the first to break decisively with the medieval doctrine of usury. The Genevan Reformer perceived no principled objections to usury. ¹⁸ That said, the scholars in question also recognised that Luther at times made more realistic pronouncements accommodating human weakness, and that Calvin qualified his defence of usury with numerous restrictions that effectively placed it beyond the reach of saints. These nuances were soon forgotten, however, and what remained was a caricature that portrayed Luther as a backward-looking peasant's son and Calvin as a modern urbanite. ¹⁹

Scholarly debate on the Reformation and the doctrine of usury continues to this day. Generally speaking, the perceived differences of opinion between Luther and Calvin appear to be narrowing, certainly with respect to their practical implications. Nevertheless, the sense remains that with Calvin—the father of the Reformed branch of Protestantism with which we are concerned here—something genuinely new occurred. Our guide through the scholastic landscape, Noonan, presents him, together with the French lawyer Molinaeus, as the first advocate of a genuine ‘counter-theory’ of usury. Unbound by canon law and wary of scholastic subtleties, Calvin replaced the proliferation of common rules and exceptions with two guiding considerations: charity and equity. All scriptural passages traditionally levelled against usurers were either directed toward the observance of these two principles and/or belonged to Jewish political law and were therefore no longer binding. Whether and in what cases usury on a loan became biting or unjust usury was left to the determination of individual consciences. According to Calvin, an absolute divine prohibition of usury as such did not exist.

For believers who wished to keep a clear conscience when lending money or goods, Calvin's writings offered various guidelines. These can be found in several Old Testament commentaries and were also brought together in Calvin's famous letter to Claude de Sachins, who sought his advice on these matters. ²⁰ In the letter, first published posthumously in 1575 as Responsum de usuris, the Genevan theologian listed seven such guidelines: (1) no usury may be exacted from the poor; (2) one should not be so focused on profit as to neglect other duties; (3) a loan must accord with natural equity and the Golden Rule; (4) the debtor's profit should equal or exceed the creditor's; (5) what is permitted to us is not to be judged by ‘the common and received custom,’ but by God's Word; (6) one should consider the public interest in addition to private interests; and (7) the rate of interest may not exceed what is permitted by the public laws of the region or place. Just prior to this list, Calvin mentioned an important eighth directive: (8) one may not make one's living from usury. Even this list alone suggests that Calvin tolerated usury more than he recommended it. As he explicitly stated elsewhere, it is difficult to avoid harming one's neighbour in the taking of usury, and it would be preferable if all usury were abolished.

Calvin's views, which in any case presented a new perspective, were adopted by several of his students both in and outside Geneva. Direct influence can, for instance, be seen in the work of Viret and Daneau. ²¹ Despite their plausibility, however, his arguments were not universally accepted in the Protestant world at the time. While the Reformed Church of France took a stance that might be called Calvinian, the Church of England opposed usury. Some of its bishops openly criticised Calvin on the subject. The campaign against usury was led by the Bishop of Salisbury, Jewell, whom Cloppenburgh mentioned in his Christian Instruction. Dissenting voices came from a number of Puritan theologians, some of whom would later move to the Dutch Republic.

This naturally brings us to the next question: what about that ‘Calvinist’ federation of seven northern provinces that came into existence between 1579 and 1588?

Usury in Early Dutch Reformed Theology

According to church historian Karl Holl, Dutch Calvinism imported its teachings on usury from France. This process was mediated through the exchange of leading theologians. Holl notes, for instance, that Daneau—whom we have just presented as a follower of Calvin—taught at Leiden in 1581. ²² In his Ethices Christianae, the first work of Reformed ethics, Daneau sided with his teacher in declaring that the Old Testament laws against usury were political, and that taking usury from profit-seeking individuals was permissible. As we will see, he was not the only Frenchman to seek intellectual or physical refuge in the Dutch Republic.

The same is true for the author of what appears to be the first statement on usury on Dutch soil: Jeremias Bastingius. It can be found in his 1588 Latin exposition of the Heidelberg Catechism, in a discussion of the eighth commandment. Explicitly referring to Calvin's commentary on Ezekiel, Bastingius distinguished between foenerari, which he understood as taking biting usury, and foenus accipere, charging (moderate) usury. Those, and only those, who make a profit on loans to the poor ‘will not dwell in the tabernacle of Jehova’ (i.e., will be damned). He applied this judgment particularly to faeneratores and usurarii, probably denoting people who made a living from usury.

Bastingius's commentary was later translated and expanded by his Dordrecht colleague Hendrik van den Corput. Van den Corput added that it is reasonable to enjoy a benefit from lending money to a neighbour, especially if the borrower is wealthier, and that God's law prohibits only oppressive usury. He declared that the question of how much profit one may make is a political one: determining the rate of interest is up to the worldly policie. However, the demands of Christian love may require one to remain below the legal limit.

The analysis of Bastingius and van den Corput was to become characteristic of Dutch Calvinist theology. Almost all theologians and ministers who came after them repeated the conviction that Scripture does not contain a universal ban on usury; that loans must be compatible with Christian love—and therefore that usury from the poor and needy is sinful; and that setting the maximum rate of usury is the responsibility of the magistrate. ²³ Often, extrinsic interest titles were either ignored or tacitly subsumed under usury. Occasionally, new arguments were offered. For example, in 1596 a student named Hendrik van Veen defended the fertility of money in a theological disputation. Contra Aristotle, who had argued the opposite, he stated that while by nature money is sterile, ‘by use it is very fertile.’ ²⁴ Explicit references to Calvin, as in Bastingius, became scarcer. It is likely, however, that a few mentions of the principle of ‘charity and equity’ in lending echoed his work. ²⁵

Although usury was widely tolerated, a number of exceptions should be noted. First, there was a Dutch minister at Schiedam named Ruardus Acronius, who joined the opponents with a lengthy discussion of usury. ²⁶ While recognising the legitimacy of interest, he did not allow for damnum emergens from the beginning of a loan, nor for any form of lucrum cessans. To make a commerce of interest or to use it as a source of profit-making was, for Acronius, unacceptable. The authorities he cited included Plato, Aristotle, and Cicero, several Church Fathers, Aquinas, and, on the rate of usury, the Reformed theologian Zanchius.

Second, there exists a curious book chapter by Kampen minister Daniel de Zouter (Souterius), meant as an admonition against usurers. ²⁷ It seems that he was not so much targeting usury itself as those who made it their profession (geprofessioneerde woeckeraers), specifically Lombards and Jews. Interestingly, the only modern testimony against usury that he presented came from Luther (‘Tomo. 7’). De Zouter's discussion of the difference between professional usury and commerce suggests that he also relied on Daneau's Ethices. ²⁸

Third, there is a little treatise on lending at usury by Dominicus Baudius, who, like De Zouter, was of French-Flemish descent. ²⁹ Trained as a theologian at Leiden and Geneva, Baudius became an extraordinary professor of rhetoric and history at the university of Leiden. In his De foenore commentariolus (1615), he claimed that foenus (a less common term for usury) was gravely condemned by the word of God and the judgment of all wise men. At the same time, he expressed the belief that, since this evil was ineradicable, it would be better to install a professional moneylender in each city, who would be granted a certain amount of leeway to lend at a fixed usury rate and against collateral. Fearing the opposition of the ‘Senate of Theologians,’ Baudius argued that such a measure could be tolerated if the public interest (utilitates reipublicae) demanded it.

Fourth and finally, Franeker professor of theology Sibrandus Lubbertus defended the sterility of money, apparently unimpressed by the disputation of 1596 discussed earlier. As he wrote in his commentary on the eighth commandment: ‘Money is a sterile thing; therefore, to take profit from it as though it were a fruitful thing is contrary to nature. Hence Sacred Scripture so strictly forbids usury.’ ³⁰

The three most authoritative statements on usury were published in the four decades preceding Cloppenburgh's Christian Instruction. These were: an appendix to a commentary on Leviticus titled De usuris by Leiden professor Junius; a 22-page section, De mutuo et usura, drawn from lectures on Exodus by another Frenchman who ended up in Leiden, Rivetus; and a chapter, De contractu usurario, from Amesius’ widely read book on cases of conscience.

In a scholastic vein, Junius carefully analysed the mode (modus: from whom and how much?), end (finem: with what intention?), outcome (eventum: is there a profit that can be shared?), and circumstances (circumstantiae) of usury. ³¹ The latter he further subdivided into the thing (res), the time (tempus), the place (locus), and the situation (casus), recognising compensation for risk (as in the case of a maritime loan) and for costs. Junius concluded that usury is lawful, provided it is not taken from the poor, and that four rules are observed: namely, that the mode is characterised by equity, the end by charity, the outcome by honesty and good faith, and the circumstances are properly weighted. It should be noted that Junius did not allow for profit-seeking loans nor, implicitly, for any lucrum cessans.

Rivetus actually wrote on usury on two different occasions. His commentary on Exodus 22:25—which Cloppenburgh referred to as Rivetus’ Diatriba de usuris—built upon a French work in which he explained the differences between Roman Catholic and Reformed doctrine. The latter book, which appeared in both Dutch and Latin translations, also contained a section titled De usura. ³² In it, Rivetus responded to the objections of Jesuit Archbishop Guillaume Baile to Calvin's letter to Sachins. Interestingly, he not only quoted large portions of the letter but also attempted to fight fire with fire by citing the views of various theologici scholastici. ³³ To accuse Calvin of heresy was, in his view, hypocritical, since various scholastics of note approved of several grounds for charging interest. Indeed, they ‘denounced usury verbally, while nonetheless endorsing it in many forms under different euphemisms.’

In 1632, Rivetus, now a professor at Leiden, presented a greatly expanded defence of usury, in which he once again took up the cause of Calvin. ³⁴ He began by distinguishing between different types of loans, explaining that the discussion focused on commercial loans, where debtors aimed at making a profit. Was it lawful to receive something beyond the principal from such borrowers? It was on this question—not on loans to the poor—that opinions differed. As Cloppenburgh would do a few years later, Rivetus was quick to acknowledge that critics of usury could be found among the ‘orthodox’ (i.e., Reformed theologians) as well as Lutherans. In what followed, he gave a detailed account of various arguments pro and contra. Following Calvin, Rivetus established that Scripture does not present a universal prohibition of usury. Furthermore, he argued, the absence of usury in commercial loans would demonstrate a lack of equity, gratitude, and charity on the part of the borrower. Finally, he reasoned that the role of usury in loans was not fundamentally different from the creditor's profit in other commercial contracts, ³⁵ or from the various interest titles distinguished by the scholastics—which all ultimately amounted to compensation for emerging damage or cessation of profits. Rivetus, in short, could find no harm in usurious loans to the better-off.

The final author to be discussed here is a theologian who fled England for religious reasons and became a professor at Franeker: William Ames. ³⁶ Known as Amesius, he continued the Dutch academic tradition by downplaying the distinction between usury and interest, allowing for both. A new emphasis in his work was the explicit approval of profit-making as a motive for lending money. Indeed, this was precisely how Amesius defined usury: ‘profit sought from a loan’ (lucrum ex mutuo quaesitum). Traditional arguments against it, such as the alleged sterility of money, he considered flawed. Scripture did not forbid usury unless it was exacted from the poor, was biting, repugnant to charity, or exceeded legal limits. ³⁷

Conclusions and Lessons

This article has examined Reformed views on usury by tracing the development of early Dutch Reformed theology. In doing so, it has challenged the common assumption that in the Dutch Republic serious scholarly reflection on the subject began with Grotius in the 1620s. The first theological texts addressing usury appeared in the late 1580s, while more elaborate treatments began with Junius's discussion of 1598. Given that theology was one of the four academic disciplines—and certainly not the least respected, the narrative of Grotius's primacy requires reconsideration. Based on what we found, Hyma's claim that ‘Dutch Calvinists up to the year 1650 developed no new theory of interest, because they were unwilling to break with anything that had been said in the Bible [and] were more anxious about this point than most of the scholastic writers’ must also be questioned. In fact, Dutch positions were surprisingly liberal, in that usury itself, and not merely interest, was generally approved. This stance was unheard of in other Protestant regions and necessarily entailed new interpretations of biblical prohibitions of usury.

This brings us to Calvin's views, which opened the door to the more liberal position. To what extent can Dutch Calvinism be said to have followed him ‘scrupulously’ and ‘throughout’? That the Genevan Reformer was one of their sources of inspiration cannot be doubted. We have seen that the earliest statements on usury explicitly referred to his work, and that Rivetus defended his Responsum de usuris at length. Yet Calvin was not the sole authority for these authors. Zanchius, Danaeus, and even Luther were among their influences as well. It is clear that most Dutch Calvinists followed Calvin in his interpretation of the biblical texts on usury. When it came to his eight rules of conscience, however, the fourth (on the equality of profits), sixth (on the public interest), and eighth (on professional moneylending) were not always mentioned or implied. From this it follows that there was no question of a strict or complete adherence to Calvin's views. Over time, the Dutch position tended toward encouraging rather than merely tolerating usury.

Finally, what can we learn from this episode in the history of the prohibition of usury? Apart from the fact that the Dutch played a formative role in normalising what are today known as interest-bearing loans, three lessons can be drawn from the two most advanced works of this period: Rivetus's academic commentary on Exodus 22:25 and Cloppenburgh's Dutch reworking of it.

First, they teach us an important historical lesson: namely, that there was no single Reformed position in the debate on usury. As we have seen, both Rivetus and Cloppenburgh compiled lists of like-minded Reformed teachers; yet they were quick to note that in England and Switzerland a number of highly learned Reformed theologians sided with the scholastics. In doing so, they demonstrated an awareness of the diversity of opinion within the Reformed ranks. While it is sometimes suggested that Calvin once and for all formulated the Reformed position, he neither had the only nor the final word on the matter. Evidently, the move away from the scholastic framework and the return to Scripture with a new hermeneutic left room for differing interpretations. When this insight is extended to what may be called contemporary forms of usury, a similar breadth of opinion can be expected (though this is not to say that we should cease attempting to persuade our opponents, as truly Reformed thinkers are inclined to do).

Second, Rivetus and Cloppenburgh warn against viewing the distinction between acceptable and sinful usury too narrowly through a legal lens. Building on Rivetus's observation that loans resemble other commercial contracts devised for profit-making, Cloppenburgh argued that they were all manifestations of ‘making money with money.’ Although loans were technically—or indeed legally—distinct from obligations, annuities, and the like, they arose from the same human desire for gain. Since this desire was, to some extent, natural, Cloppenburgh suggested that the proper test was whether such practices benefited the parties involved and, preferably, commerce and society at large. If so, who could object? Although Cloppenburgh showed little awareness of the long-term effects on, for instance, economic inequality, his move beyond legal forms to the deeper motivations and consequences of financial instruments remains helpful.

Third and finally, the two Dutch theologians offer guidelines for individual conduct. At the end of his treatise, Cloppenburgh formulated three rules of conscience that echoed those of Rivetus and several other authors discussed in this article. First, Christians should not be content with merely adhering to the legal limits on usury as set by the magistrate, but should strive for greater moderation. In other words, they should not seek to maximise profits from loans, but rather aim for what is sufficient, as determined by love for their neighbours and for themselves. Second, it was undesirable for them to abandon their current callings in order ‘to occupy themselves solely with the easy profit of generating and enriching money with money’—where the word ‘solely’ still recalled Calvin's eighth rule, namely that Christians should not be professional usurers. Third, Cloppenburgh advised against investing all one's savings in loans and other financial instruments, so that some resources would remain available for almsgiving to the poor. Taken together, these three rules have lost none of their relevance.