What Is Reformation Day? Why 31 October Matters — and What the Reformers Rediscovered

On 31 October 1517, a monk and university professor in the small German town of Wittenberg published a list of 95 arguments for debate. Martin Luther wanted to talk about indulgences. He ended up changing the Western church.

What Happened in 1517

In Luther's day, the church was selling indulgences — certificates promising reduced punishment for sin — partly to raise money to rebuild St. Peter's Basilica in Rome. Luther, troubled by what he saw as people buying assurance that only God could give, wrote his 95 Theses against the practice.

Tradition says he nailed them to the door of Wittenberg's Castle Church, which served as the university's noticeboard. Historians still debate exactly how they were posted, but there's no doubt that he sent them to his archbishop on 31 October — and that, thanks to the new printing press, they spread across Germany within weeks.

The first thesis set the tone: when Jesus said "Repent," He meant the whole life of a believer to be one of repentance.

"Here I Stand"

Luther was summoned before the Diet of Worms in 1521 and ordered to take back his writings. He refused unless convinced by Scripture and plain reason, saying his conscience was "captive to the Word of God." The words most often remembered — "Here I stand, I can do no other" — appear in the earliest printed accounts, though whether he said them exactly is debated.

He was declared an outlaw, hidden in Wartburg Castle by a protector — and there he translated the New Testament into German, published in 1522, so ordinary people could read the Bible for themselves.

The Five Solas

The Reformers' convictions are often summed up in five Latin phrases, each with the word sola, "alone":

• Sola Scriptura — Scripture alone is the final authority for faith and life.
• Sola Gratia — salvation is by grace alone, a gift we cannot earn.
• Sola Fide — we are made right with God through faith alone.
• Solus Christus — in Christ alone, the one mediator between God and humanity.
• Soli Deo Gloria — for the glory of God alone.

At the heart of it was a verse Luther said opened the gates of heaven to him: "The righteous will live by faith" (Romans 1:17). Paul says it plainly elsewhere: "For it is by grace you have been saved, through faith — and this is not from yourselves, it is the gift of God — not by works, so that no one can boast" (Ephesians 2:8-9). That is the gospel.

Who Else Was Involved?

Luther was not alone. Ulrich Zwingli in Zurich, John Calvin in Geneva and William Tyndale in England — whose English New Testament, first printed in 1526, cost him his life — all pressed for reform and for the Bible in the language of the people. Earlier voices such as John Wycliffe and Jan Hus had raised many of the same concerns more than a century before.

How Reformation Day Is Kept Today

• Lutheran and many other Protestant churches mark Reformation Sunday — in the U.S. often the Sunday on or before 31 October — with hymns such as Luther's "A Mighty Fortress Is Our God."
• 31 October is an official holiday in several German states and in Slovenia and Chile; Germany made it a nationwide holiday for the 500th anniversary in 2017.
• Some churches hold Reformation Day events as an alternative to Halloween on the same night.

The day has also become a moment for honest conversation between traditions. On 31 October 1999, the Lutheran World Federation and the Catholic Church's Pontifical Council for Promoting Christian Unity signed the Joint Declaration on the Doctrine of Justification, stating a shared understanding of justification by grace through faith, while acknowledging remaining differences.

Why It Still Matters

The Reformation wasn't mainly about a door, a date or a church split. It was about a question every person still asks: how can I be right with God? The answer the Reformers found in Scripture is the same one we tell in our stories of people being born again today — not by what we do, but by what Jesus has done.

It's also a reminder of what an open Bible can do. Today, more than 500 million Christians still live with restricted access to Scripture. The work of putting God's Word into people's hands isn't finished.