In some ways, Protestant reformers' views were closer to traditional Catholic ethical thought than they were to much of the Protestant tradition that has followed them, Tuininga writes.
The reformers broke dramatically with the Roman Catholic Church when it came to the doctrines of salvation and ecclesiology.
They did not do so with respect to ethics. In fact, in some ways, their views were closer to traditional Catholic ethical thought than they were to much of the Protestant tradition that has followed them.
On any number of ethical and political topics, the thought of John Calvin is closer to that of the medieval theologian Thomas Aquinas than either of them is to any number of Protestant ethicists today.
For many years, Protestant theologians preferred to contrast Protestant ethics with Roman Catholic ethics.
Protestant ethics was centered on biblical authority, they argued, while Roman Catholic ethics, because of its natural law tradition, was far too enamored with the powers of human reason.
Protestants emphasized the consistency of the Bible's moral teaching, summarized in the Ten Commandments, while Roman Catholics wrongly contrasted the new law of the gospel with the old law of Israel.
Protestants called all Christians to the same level of righteousness, while Catholics taught that certain Christians - clergy, monks and nuns - are called to follow the higher evangelical counsels of Christ's teaching.
In some ways, to be sure, the reformers themselves paved the way for this contrast.
While they upheld the traditional Christian teaching that God's moral will is written on the human heart and in the creation order (in other words, natural law), they expressed fresh skepticism regarding the capabilities of human reason.
While they insisted that Christians were to interpret the Ten Commandments in light of the law's fulfillment in Christ, they downplayed any meaningful contrast between the ethical teaching of the Old and New Testaments.
They emphasized the vocational ordinariness of the Christian life and softened the radicalism of Christian discipleship.
Over time, however, many evangelical Protestants virtually abandoned the concept of natural law altogether, in favor of an emphasis on biblical authority.
And because of their emphasis on the Ten Commandments as the perfect expression of God's moral will, they largely ignored the distinctiveness of the New Testament's virtue-oriented, Christocentric approach to ethics.
Thus, one could look far and wide for any meaningful Protestant study of Christian virtues akin to that of Aquinas.
The conflict between Protestant and Catholic political theologies grew even sharper.
Protestants embraced political liberalism, religious freedom and natural rights quite early, while the Catholic Church fiercely rejected all such modern political ideologies as alien to the one true faith of Catholicism.
In the age of brutal religious wars that ripped apart Europe and rippled throughout the world, Protestants identified the papacy as the antichrist, always fearing that Catholics sought to rob them of their liberties and force them into submission to the pope.
Two major forces began to change all of this in the latter part of the 20th century.
First, the Roman Catholic Church opened itself ecumenically to Protestantism after Vatican II. Second, Protestants and Catholics alike came to view secularism and the increasing abandonment of Christianity as the far graver threat.
Catholic thinkers sought to learn from the Protestant tradition's embrace of political liberalism. Protestant theologians became interested in the ways in which the reformers stood in continuity with pre-reformation Christian tradition.
Catholic social thought began to emphasize the ideals of liberty and equality, while Protestant ethicists began to rediscover the value of the natural law tradition, with its rich potential for moral reasoning in pluralistic contexts.
Catholics came to appreciate the active role of the Bible in Protestant ethics, while Protestants sought to glean from the Catholic liturgical tradition a fresh understanding of the role of worship in moral formation.
Catholics looked to Protestants for a sense of the virtue of ordinary Christian vocations, while Protestants looked to Catholics for insight into the nature of a Christian virtue ethic.
The result has been a growing convergence among Reformed and Catholic ethicists, even as important differences remain.
Matthew J. Tuininga is assistant professor of moral theology at Calvin Theological Seminary and author of "Calvin's Political Theology and the Public Engagement of the Church: Christ's Two Kingdoms." This article originally appeared in the Fall 2017 edition of Forum, a publication of Calvin Theological Seminary. It is used with permission. His writings also appear on his blog, Christian in America, and you can follow him on Twitter @MJTuininga.
Editor's note: This is the first of a two-part series. Part two is available here.