501 years ago this month, Martin Luther nailed his famous 95 Theses to the door of the Wittenberg church. What followed was an earthquake along theological fault lines rivaled only by the Great Schism of 1054. Whereas the Great Schism divided the Church between the Roman Catholic Church in the West and the Orthodox Church in the East, Luther’s ideas divided the Western church between the Roman Catholic Church and the various Protestant churches. The effects of these two massive schisms are alive and well today.
Following Luther, Protestants soon diversified their theology. We see this diversity today: Baptists, Lutherans, and Presbyterians are all Protestant. However, they are quite different in their theology and praxis. Nevertheless, from Luther’s time to the present, several ideas have become distinctive of Protestant theology. Among these uniquely Protestant ideas are the five solas of Reformation theology.
1. Sola Fide
Like the rest of the solas, sola fide is a Latin phrase that translated to faith alone. This sola was perhaps the first sola, which Luther discovered while writing lectures on the book of Romans. Luther, who had a profound understanding of his own depravity before God, read Romans 1:17: “In the gospel the righteousness of God is revealed—a righteousness that is by faith from first to last, just as it is written: ‘The righteous will live by faith.’” By studying this verse, Luther realized that the Catholic Church had taught him poor theology: He could never receive the sacraments enough, confess enough sins, or say enough Hail Marys to earn righteousness before God. As he had so painfully realized, none of these ostensibly good works could give him salvation.
In Romans 1:17, Luther learned that the righteousness which he had pursued for so long was held out in the gospel to be received on the basis of faith. Instead of doing enough good works to make ourselves righteous before God, the gospel credits Christ’s righteousness to us on the basis of faith alone. Thus, no works can make us good; instead, God declares us righteous sola fide, by faith alone.
2. Sola Gratia
Sola gratia has a strong relation to sola fide. Sola fide says we’re saved through faith alone, and sola gratia says that we’re saved by God’s grace alone. In this way, these first solas are essentially a summary of Ephesians 2:8. We’ve already said that Protestants believe that God credits us with righteousness on the basis of our faith; sola gratia says that God’s grace is the only reason that he decides to give us salvation. I am not saved because I did enough good works to merit God’s favor; instead, Christ came, died, and rose from the grave by the grace of God. Similarly, God calls me to repent of my sins and find new life and freedom in the cross by his grace alone. I didn’t do anything to deserve or earn my salvation. Instead, every part of salvation is driven by God’s grace alone.
3. Solus Christus
Solus Christus means that the free, undeserved righteousness which God gives us by grace alone through faith alone is available through Christ alone. Christ lived the holy, perfect life which satisfied God’s demands while I was still incapacitated by sin. Christ took my punishment and died the death that I deserved—he paid the debt that I owed but couldn’t afford. Christ then rose from the grave to attain the victory over death, hell, and the grave that I so badly needed but could never win. Thus, everything necessary for my salvation was accomplished and is found in Christ alone. I can never save myself, no church can die for me, no saints can purchase my redemption. Christ alone has this awesome power.
4. Sola Scriptura
Sola scriptura means scripture alone. According to sola scripture, any religious body that contradicts the other solas—whether Protestant, Catholic, or Orthodox—is wrong by default because this religious body is contradicting scripture. If the other solas are grounded in scripture, nothing has the power to stop them. In this sola, Luther definitely had the Catholic Church in mind.
From before Luther to the present day, Catholic theology has recognized sources of religious authority in addition to the Bible. Indeed, this is the foundational difference between Catholics and Protestants. Modern Catholic theology holds that the Pope is infallible; thus, the Pope can create or modify doctrines with God’s authority. Catholics also believe that the traditions of the Catholic Church are a powerful source of authority on the doctrine and practice of the Catholic Church.
As Luther began to study the Bible, he came to the quintessentially modern idea that the religious authorities didn’t necessarily represent God. Like Jesus who had rebuked the religious authorities 15 centuries prior for espousing the doctrines of men above those of God, Luther realized that doctrinal statements are only binding insofar as they reflect scripture. Thus, Luther, and all Protestants who follow in his steps to some extent, do not accept the authority of the Pope, ecumenical councils, or creeds. We value these things and affirm them to different extents; indeed, we even have our own, uniquely Protestant confessions of faith! However, we believe that religious authorities are only binding insofar as they reflect scripture. Scripture alone is the authority in religious matters. Consequently, any time that a pastor, Pope, or presbyter contradicts scripture, we believe that person is wrong.
5. Soli Deo Gloria
The solas present a pleasant picture of the gospel indeed. According to the solas and to Protestant theology by extension, we can never do enough good works to merit our salvation; fortunately, however, in the gospel, God has freely opened the door to our salvation. All we need do is believe. At this point, you may be wondering why God has done so much for us. Luther aptly summarized this feeling when, on his deathbed, he wrote: “We are beggars. This is true.” We are certainly mere beggars before the awesome majesty and terrifying holiness of God. We have nothing to give God. Everything we have, we have received from, it is all his! Not only are we indebted to him, but we have also ruined his good gifts. As Isaiah says, “all our righteous acts are like filthy rags.” Paul goes further and says that we “have together become worthless” before God. There is no reason for God to pursue you. He gains nothing and loses everything in the gospel.
The final sola, which means glory to God alone, answers the question of why: God redeems us for his glory alone. Since we don’t contribute anything to our salvation, it is accomplished by God alone. Thus, he receives all the credit from our salvation. Furthermore, when we do good works as believers, he receives all the glory from our good works because he is the one who gave us the ability to do good works. Because all of life and salvation is done for the glory of God alone, we should never be puffed up with pride in our own eyes as if we had accomplished anything worthwhile. God is the one who paid the price for our salvation, he purchased us through the blood of Christ, he regenerated us unto new life, and he is the only with the right to receive any of the credit. Jesus summarizes this idea when he says, “when you have done everything you were told to do, [you] should say, ‘We are unworthy servants; we have only done our duty.’”
Notes & Sources
 Romans 1:17, all scripture quotations are NIV.
 Eric Metaxas, Martin Luther: The Man Who Rediscovered God and Changed the Whole World (New York: Viking, 2017), 432.
 Isaiah 64:6.
 Romans 3:12.
 Luke 17:10.