It was time for the believers living in Rome to stop arguing. Some Jewish Christians were reluctant to give up some ceremonial aspects of their faith, but others were not so reluctant. One disagreement involved the food they ate. Paul spoke into this unstable dispute, “I know and am convinced in the Lord that nothing is unclean in itself; but to him who thinks anything to be unclean, to him it is unclean” (Rom. 14:14). Paul was not saying that morality is subjective but rather emphasizing the significance of a believer’s conscience.
Scripture is clear on matters of conscience. An act becomes sinful for a believer if it causes him to transgress his own conscience (Rom. 14:23; 1 John 3:21). For this reason, Martin Luther stood before Charles IV at the Diet of Worms in 1521 and declared that his conscience could not allow him to be coerced by ecclesiastical and political authority. John Calvin also believed that faith cannot be coerced. Both placed emphasis on man’s accountability to the Scriptures alone and on freedom of conscience.
These two foundational ideas would serve as principles for advocates of religious liberty later on. In this article, we will explore Luther’s and Calvin’s beliefs about religious liberty and see what implications they have for modern day views of freedom of conscience.
Early Formulations of Religious Liberty
Knowledge of God is revealed by His self-disclosure. Special revelation is needed to understand this self-disclosure. Thankfully, God has manifested Himself in the Old and New Testaments. The reformers understood this truth as seen in the doctrine of sola scriptura, which holds the Scriptures to be the only trustworthy rule of faith and practice. Luther and Calvin both used this doctrine as the foundation for freedom of conscience.
The Holy Scriptures were of highest importance to Luther’s theology. He believed that both the content and the transmission of God’s Word provided an essential means of grace for the church. Luther understood the gospel and the message of Jesus Christ (who is the Word incarnate) to have highest authority in the believer’s life. This led Luther to conclude that the Word of God has authority over the church and our conscience.
On April 17, 1521, Luther was told he must retract his views on Scriptural authority. After praying for long hours and consulting with friends, he was given the chance to rearticulate his views before the Diet of Worms on April 18, 1521. He did not renounce his views. Instead, Luther declared:
Since then your sere Majesty and your Lordships seek a simple answer, I will give it in this manner, neither horned nor toothed. Unless I am convinced by the testimony of the Scriptures or by clear reason (for I do not trust either in the pope or in councils alone, since it is well known that they have often erred and contradicted themselves), I am bound by the Scriptures I have quoted and my conscience is captive to the Word of God. I cannot and I will not recant anything, since it is neither safe nor right to go against conscience. May God help me. Amen.
Luther clearly believed that no source of authority would suffice other than God’s Word. How does his pronouncement relate to religious liberty?
Luther does not directly address religious liberty in his Ninety-five Theses. However, we see the emphasis he placed on freedom of conscience in his defense at the Diet of Worms. Noting this connection between Luther’s defense and freedom of conscience, Joseph Loconte writes,
Luther insisted that the state possessed neither the competence nor a mandate from heaven to intrude into spiritual matters. “The soul is not under Caesar’s power,” he wrote, “he can neither teach nor guide it, neither kill it nor make it alive.” Other reformers argued for a radical separation of church and state, a concept that Luther ultimately rejected. Others went further in defending the rights of all religious believers, even heretics and non-believers, in civic and political life.
“The soul is not under Caesar’s power,” Luther writes. Certainly, Caesar has legitimate power, but not unlimited power over man’s soul.
Luther may stand out as the key figure of the Reformation, but John Calvin offered a clearer understanding of the conflict between the authorities of Scripture and of government on matters of conscience.
Calvin, too, understood the Word of God to be the ultimate authority of conscience. Scripture alone deserves final authority for the believer. However, he also encouraged believers to obey political officials within the limits of conscience. Calvin opened his 1536 edition of the Institutes of the Christian Religion with an appeal to King Francis I of France on behalf of persecuted Protestants, through which he sought to “defend the church against furies” and “to embrace the common cause of all believers” against “overbearing tyranny.”
Another key concept Calvin formulated was his advocacy for the freedom of conscience for people of other religions. This idea is especially important for our understanding of religious liberty today. The church must not only respect the beliefs and consciences of others within our own ranks but also those of people who practice other religions. Calvin wrote:
We ought to strive by whatever means we can, whether by exhortation and teaching or by mercy and gentleness, or by our own prayers to God, that they may turn to a more virtuous life and may return to the society and unity of the church. And not only are excommunicants to be so treated, but also Turks and Saracens, and other enemies of religion. Far be it from us to approve those methods by which many until now have tried to force them to our faith, when they forbid them the use of fire and water and the common elements, when they deny them to all offices of humanity, when they pursue them with sword and arms.
Freedom of conscience for everyone should not be equated with the view that truth is relative. We support freedom of conscience for everyone because we desire an environment where gospel proclamation freely occurs from one conscience to another (2 Cor. 4:2).
For Martin Luther, Christians navigate two different realms. According to Luther, God has established an earthly kingdom and a heavenly kingdom. Luther believed humanity to have obligations to both realms. The earthly kingdom consists of civic life where man obeys laws set forth by human institutions while the heavenly kingdom consists of redemption and hope. Luther saw these two kingdoms as parallel realms mirroring forms of justice, truth, and order. However, these realms remain separate and distinct.
John Calvin used similar language as Luther to argue for two distinct realms. Thus, Luther and Calvin each affirmed two distinct realms. However, they did not conceive of these realms, or in how they interrelate, in the same way, Luther giving way to the Lutheran tradition and Calvin the Reformed tradition. Calvin wrote:
[O]ne aspect is spiritual, whereby the conscience is instructed in piety and in reverencing God; the second is political, whereby man is educated for the duties of humanity and civil life that must be maintained among men. . . . There are in man, so to speak, two worlds, over which different kings and different laws have authority.
This idea that there existed two realms, kingdoms, or spheres of authority, along with the belief that man’s conscience is free from coercion, would serve as the foundation for religious liberty advocates later on.
The reformers give us a foundation upon which to build our thinking about religious liberty. Therefore, we should think deeply about how religious liberty shapes our doctrine and duty. We don’t advocate freedom of conscience to advance the agenda of a certain political party. We advocate freedom of conscience so we can promote peace, joy, love, edification, and even evangelism among the members of the Body of Christ (see Rom. 14:17, 19; 15:8-13; 1 Cor. 8:1; 10:31-33). We should accept the right of every person bearing the image of God to worship, even if there are differences of beliefs. The religious world was changing for the reformers, and the religious world is changing today too. Ministers may withhold communion from non-believers, but no minister or state official should have the power to persecute or coerce someone because they don’t hold to the same beliefs as we do.
“A Christian is a perfectly free lord of all, subject to none. A Christian is a perfectly dutiful servant of all, subject to all. These two theses seem to contradict each other. If, however, they should be found to fit together they would serve our purpose beautifully.” Luther believed these two contradictory ideas can fit together. We should also aim to see that they are kept together and never separated.
 All Scriptural quotations and references come from the New American Standard Bible.
 See Timothy George, Reading Scripture with the Reformers (Downers Grove, MI: IVP Academic, 2011).
 “Luther at the Diet of Worms, 1521,” in Luther’s Works: American Edition, ed. Jaroslav Pelikan and Helmut Lehman, 55 vols. (St. Louis: Concordia Publishing House; Philadelphia: Fortress Press, 1958-1986), 32:112.
 Joseph Loconte, “Luther’s Challenge to the Conscience of the West,” Religious Freedom Institute, July 19, 2016; https://www.religiousfreedominstitute.org/cornerstone/2016/7/19/luthers-challenge-to-the-conscience-of-the-west; accessed September 26, 2017; Internet.
 “Letter to Melanchthon” (June 28, 1545) in Letters of John Calvin, ed. Jules Bonnet (Philadelphia: Presbyterian Board of Publication, 1858), 1:467.
 John Calvin, Institutes of the Christian Religion (1536), trans. Ford L. Battles (Atlanta: John Knox Press, 1975), 2.28.
 Ibid., 6.13.
 For further study on this topic, see Russell Moore, Onward Engaging the Culture Without Losing the Gospel (Nashville: B&H, 2015), 138-60.
 Martin Luther, On Christian Liberty (Minneapolis, MN: Fortress, 2013), 2.