One danger of being familiar with history is just that. It becomes familiar to us. Or so we think. Our familiarity with the facts, the cause-effect relationships, and the narrative may keep us from actually seeing what happened, or why what took place matters for us. The narrative of the Protestant Reformation serves as a case in point. Martin Luther (1483–1546) simply read the Bible, rediscovered the doctrine of justification by faith alone (sola fide), and preached the gospel. And in the process, he and later Reformers like John Calvin (1509–64) turned the world upside down.  Right?
Not so fast, argues Brad Gregory. Gregory, a highly trained Reformation historian, argues that the Reformation unbound the tightly-knit-together world of the Thomistic synthesis between faith and reason and the Catholic conception of Christendom in which secular and religious cohered closely together. Unknowingly, Luther unleashed a torrent that swelled into the modern world with all its post-Enlightenment problems.
In other words, the Protestant reformers unwittingly caused modernity. How? Most fundamentally by turning away from the Catholic church’s definition of dogma to the view that the Bible, not the church, determined the truth. Sola scriptura caused the problems the West has faced in modernity. 
LUTHER ON PREACHING AND PRAYER
When Luther and Calvin, though, described what led to the earth-shattering transformations of their days, with one voice they declared the recovery of the gospel and the clear preaching of that gospel which caused people to come out of spiritual darkness into light. Sola fide flowed from sola scriptura.
Luther struggled for months (or longer!) to understand how “the righteousness of God” (which he thought must refer to God’s retributive justice) could be “good news” in Romans 1:16–17. After finally seeing that God graciously imputed Christ’s righteousness to his people,  Luther described the doctrine of justification by faith alone as “the summary of all Christian doctrine” and “the article by which the church stands or falls.”  In another place he observed, “Nothing in this article [of justification] can be given up or compromised, even if heaven and earth and things temporal should be destroyed … On this article rests all that we teach and practice against the pope, the devil, and the world.” 
Luther argued that the tide of the Reformation swept forward on the preaching of the Word of God alone: “I simply taught, preached, wrote God’s Word; otherwise I did nothing. And then, while I slept, or drank Wittenberg beer . . . the Word so greatly weakened the papacy that never a prince or emperor did such damage to it. I did nothing. The Word did it all.” 
There you have it. The Word did it all.
In order for the church to gather as the people of God, there must be both the preaching of the Word of God and prayer, Luther exhorted. “At each service a passage of Scripture is to be read and then interpreted. This is to be followed by the praying of the Psalms and other prayers.”  Luther stressed that the Word was the very Word of Christ. And Christ brought the Word to bear with power by means of his Spirit. Although “God uses the ordinary means of the reading and preaching of the Word by ministers of the gospel,” nonetheless the Word “becomes inward when inwardly it is received and believed. This is the work of the Holy Spirit. It is through the Word that the Holy Spirit works.” 
CALVIN ON PREACHING AND PRAYER
Calvin agreed with Luther the pioneer. He described justification by faith alone as “the main hinge on which religion turns.”  And the means of proclaiming this exquisite gospel is the ordinary preaching of the Word of God. Calvin counted it “a singular privilege” that God had consecrated “to himself the mouths and tongues of men in order that his voice may resound in them.”  Preaching is essential. In fact, nothing is “more notable or glorious in the church than the ministry of the gospel, since it is the administration of the Spirit and of righteousness and of eternal life.” 
And Calvin lived as he wrote. He preached—a lot! John Leith’s comment is apt, and understated: “The sheer volume of Calvin’s preaching is impressive.” Always conceiving of the regular preaching ministry as his primary calling, the Genevan pastor carried an impressive preaching load. For about the last 15 years of his life he preached twice on Sunday and once Monday through Saturday, on alternate weeks. Just from 1549 to 1560, he preached 2,042 sermons. According to Dawn DeVries, between 1541 and 1564 Calvin preached through “the Psalms, Jeremiah, Lamentations, Micah, Zephaniah, Joel, Amos, Obadiah, Jonah, Daniel, Ezekiel, 1 and 2 Thessalonians, 1 and 2 Timothy, Titus, 1 and 2 Corinthians, Job, Deuteronomy, Isaiah, Galatians, Ephesians, Harmony of the Gospels, Acts, Genesis, Judges, 1 and 2 Samuel, and 1 Kings.” His output included 200 sermons on the book of Deuteronomy, 174 on Ezekiel, and 189 on Acts.  When the entire corpus of Calvin’s sermons is considered, it constitutes nearly half of everything this prolific author wrote. Though Calvin preached with no notes, the Geneva city council knew what a phenom they had in Calvin. So they paid for a group of secretaries to take the preacher’s sermons down and publish them. 
Why did Calvin dedicate so much time to preaching? Simply—and incredibly—because in it God communicated to his people: “When the Gospel is preached in the name of God, this is as much as if he himself did speak in his own person.” Almighty God, who dwells in unapproachable light, communicates through the preaching of his Word. And he does so in such a way as to make the gospel go forth with power to save his elect:
The voice of man is nothing but a sound that vanishes in the air, and notwithstanding it is the power of God to salvation to all believers (saith Saint Paul). When then God speaketh unto us, by the mouth of men, then he adjoins the inward grace of his Holy Spirit, to the end, that the doctrine be not unprofitable, but that it may bring forth fruit. See then how we hear the heavenly Father: that is to say, when he speaketh secretly unto us by his Holy Spirit, and then we come unto our Lord Jesus Christ. 
Calvin believed that God spoke to his people through the ordinary means of the preaching of his Word. Through the preached Word, God saved his people. Through the preached Word, he conformed them more and more to Christ because God “will have nothing preached in his name but that which will profit and edify.” 
Another reason pushed Calvin to stress the regular preaching of God’s Word: people were often led astray from the proper means of knowing God and his will. Catholics pointed people to the church. The libertines and fanatics looked to remarkable experiences. Both were flawed, Calvin said. We know God in his Word as the Holy Spirit—who authored the book—illumines us to understand his Word. Calvin avers, “by a kind of mutual bond the Lord has joined together the certainty of his Word and of his Spirit so that the perfect religion of the Word may abide in our minds when the Spirit, who causes us to contemplate God’s face, shines; and that we in turn may embrace the Spirit with no fear of being deceived when we recognize him in his own image, namely, in the Word.” 
Both Luther and Calvin believed that the recovery of the biblical gospel of justification by faith alone was essential if people were to be born again. At the same time, the preached gospel also caused growth in Christians. For in preaching, God by his Spirit spoke. And he acted. So Luther and Calvin simply studied, prayed, and preached—and wrote, and discipled, and led, and worked themselves almost to death. And God used these flawed, but committed men to turn the world upside down.
HOW REFORMATION PREACHING CHANGED THE WORLD
The German and Swiss Reformations—and the Lutheran and Calvinist movements they led to—convulsed the world in the sixteenth century. A quick glance at the effects of the Calvinist side of the Reformation demonstrates the manner in which the preached Word built up the church. Calvin preached, pastored, and discipled others.  Not only did this lead to growth in the church in Geneva, but it also resulted in the Genevan church sending out church planters into France.
The French were quite hostile to the Protestant faith, but nonetheless the Genevan missionaries faithfully got to work. Before 1555, there doesn’t seem to have been any organized effort on Geneva’s part. But then they began sending young men—a lot of them. As Robert Kingdon recounts, “Between 1555 and 1563 the ‘Register of the Company of Pastors’ records some 88 missionaries sent, but this is only a partial number for the registers are incomplete.”  What happened from the faithful preaching of these young men is remarkable. According to Pierre Courthial, “In 1555 there were five organized Reformed churches in France; in 1559, the year the first national synod assembled in Paris, there were nearly 100; and by 1562 they numbered 2,150.”  The preached Word led to extraordinary growth through conversions and church-planting.
We could recount the manner in which the preached Word led to new life and spiritual depth in the Puritan era in England in the seventeenth century. We could also look to the way that preaching shook the English colonies in the First Great Awakening of about 1735 to 1745, fueled by Jonathan Edwards and George Whitefield. The common thread from the sixteenth to the eighteenth centuries was the faithful, clear, passionate preaching of God’s Word combined with holding fast to the doctrine of justification by faith alone. 
God by his Spirit continues to work in the same way today. The Lord blesses the same gospel, and the same ordinary preachers who trust the authority of his Word and the necessity of the Holy Spirit to bring conviction and illumination.
In the Reformation, the Word did it all. Five hundred years from now, may that be said of your ministry and mine.
 Michael Reeves winsomely presents the narrative of the Protestant Reformation in Unquenchable Flame: Discovering the Heart of the Reformation (Nashville, TN: B&H, 2010). A fuller treatment that acknowledges the religious and doctrinal focus is Carter Lindberg, The European Reformations, 2nd ed. (Malden, MA: Wiley-Blackwell, 2009).
 For Gregory’s extended argument see Brad S. Gregory, The Unintended Reformation: How a Religious Revolution Secularized Society (Harvard, MA: Harvard University Press, 2012). He highlights the negative effects of sola scriptura in “A Response to Evangelicalism” in Journeys of Faith: Evangelicalism, Eastern Orthodoxy, Catholicism, and Anglicanism , ed. Robert L. Plummer (Grand Rapids, MI: Zondervan, 2012), 165–178. Readers might be interested in two insightful reviews of Gregory’s argument, the first by Michael Horton (https://www.thegospelcoalition.org/reviews/the-unintended-reformation/), the second by Carl Trueman (https://www.reformation21.org/articles/pay-no-attention-to-that-man-behind-the-curtain-roman-catholic-history-and-the-e.php).
 See Martin Luther, “Two Kinds of Righteousness,” in Martin Luther’s Basic Theological Writings, ed. Timothy F. Lull (Minneapolis, MN: Fortress, 1989), 155–164.
 Timothy George, Theology of the Reformers (Nashville, TN: Broadman, 1988)62.
 Martin Luther, The Smalcald Articles, in Martin Luther’s Basic Theological Writings, 502–503.
 George, Theology of the Reformers, 53.
 Hughes Oliphant Old, The Reading and Preaching of the Scriptures in the Worship of the Christian Church. Vol. 4: The Age of the Reformation (Grand Rapids, MI: Eerdmans, 2002), 31.
 Old, Reading and Preaching of the Scriptures, 41.
 John Calvin, Institutes of the Christian Religion, Library of Christian Classics, 2 volumes, ed. John T. McNeill, trans. Ford Lewis Battles (Philadelphia: Westminster, 1960), 3.11.1.
 Calvin, Institutes, 4.1.5.
 Calvin, Institutes, 4.3.3.
 Dawn DeVries, “Calvin’s Preaching,” in The Cambridge Companion to John Calvin, ed. Donald K. McKim (Cambridge: Cambridge University Press, 2004), 111.
 John H. Leith, “Calvin’s Doctrine of the Proclamation of the Word and Its Significance for Today,” in John Calvin and the Church: A Prism for Reform, ed., Timothy George (Louisville, KY: Westminster/John Knox, 1990), 206–207.
 John Calvin, third sermon on Jacob and Esau, quoted in Leith, “Calvin’s Doctrine of the Proclamation of the Word,” 227, n. 31.
 John Calvin, sermon on 2 Timothy 2:16–18, quoted in Leith, “Calvin’s Doctrine of the Proclamation of the Word,” 222.
 Calvin, Institutes, 1.9.3.
 A wonderful book on Calvin’s pastoral ministry and that of the next generation is Scott M. Manetsch, Calvin’s Company of Pastors: Pastoral Care and the Emerging Reformed Church, 1536–1609 (Oxford: Oxford University Press, 2012).
 Robert M. Kingdon, Geneva and the Coming of the Wars of Religion in France, 1555–1563 (Geneva: Librarie E. Droz, 1956), 14.
 Pierre Courthial, “The Golden Age of Calvinism in France,” in John Calvin: His Influence in the Western World, ed. W. Stanford Reid (Grand Rapids, MI: Zondervan, 1982), 77.
 On the growth of Calvinism, see Jon Balserak, Calvinism: A Very Short Introduction (Oxford: Oxford University Press, 2016), and John T. McNeill, The History and Character of Calvinism (Oxford: Oxford University Press, 1954). For Calvin’s influence on missions, note Michael A. G. Haykin and C. Jeffrey Robinson, To the Ends of the Earth: Calvin’s Missional Vision and Legacy (Wheaton, IL: Crossway, 2014).