If someone bangs on your door tonight, they probably want candy. Five hundred years ago, someone banged on a door for a very different reason.

On this day in 1517—at least according to tradition—a German monk-turned-Bible-professor nailed a list of debate topics to a church door, altering the course of history.

Now, we don’t know the exact date when Martin Luther posted his Ninety-Five Theses, although he did submit them to his archbishop on October 31. What we do know is that Luther never intended to defy the church or split Western Christendom. When he challenged all comers to a debate on the sale of indulgences—which were essentially a way to buy into Heaven—he wanted to call God’s ministers back to Scripture.

But those ministers resisted. Luther wouldn’t budge, and the result was what we now know as the Protestant Reformation.

Historian Philip Schaff writes that next to the beginning of Christianity, the Reformation was “the greatest event in history.” That may be hyperbole, but not by much. If you worship in a Baptist, Methodist, Presbyterian, non-denominational, or—of course—Lutheran congregation, you’re directly affected by Martin Luther. Anglicans have been affected too, and even Roman Catholics saw reforms within that communion that came about because of Martin Luther.

And the Reformation’s influence goes far beyond the church doors. Luther’s appearance before the Diet of Worms—that famous moment when he reportedly said, “Here I stand, I can do no other,” has been called “the trial that led to the birth of the modern world.”

Our ideas about free inquiry, democracy, education, and capitalism can all ultimately be traced back to the Reformation.

And the Reformation also reemphasized ideas like the sacredness of all callings, and spheres of authority in human society. In Luther’s mind, individuals and civil magistrates, as well as the clergy, were responsible to read, understand, and obey the Bible.

As Eric Metaxas and I discuss on this week’s BreakPoint podcast, Luther came to personify the power of Scripture. In his outstanding new biography on Luther, Eric tells how this bold reformer stood at the intersection of the Middle Ages and the modern world, insisting that there is “daylight between truth and power.”

And it was this idea—that God’s written word is the highest authority in the Christian faith, available to everyone—that birthed a still more revolutionary idea: that God Himself admits us into His kingdom by grace alone.

“The Reformation,” wrote the late Episcopal priest Robert Capon, “was a time when men went blind, staggering drunk because they had discovered, in the dusty basement of late medievalism, a whole cellar of fifteen-hundred-year-old, two-hundred proof Grace—bottle after bottle of pure distillate of Scripture, one sip of which would convince anyone that God saves us singlehandedly.”

Now the fallout of the Reformation wasn’t all good, and even today Christianity is plagued with divisions, disagreements, and distortions of Luther’s project. Luther, himself, was far from perfect.

But I’m a mentee of Chuck Colson, who together with Father Richard John Neuhaus brought evangelicals and Catholics together over common cause. I pray and believe that the divisions of the 1500s—which remain real and significant to this day—can be addressed without sacrificing truth, and yet in the meantime, we can treat each other with love and grace, and should work together whenever and wherever we can.

As we mark 500 years since Luther’s initial protest, it’s clear there’s more reforming to be done on both sides of the Wittenberg door. But that’s why Reformation is not just a moment in history. It’s a posture. During the next 500 years, the sound of Luther’s hammer should call us as the people of God to conform ourselves to the Word of God, and ultimately to the Person of God in Jesus Christ.

The Reformation Turns 500: How Luther Shaped Our World

Delve further into the history of the Protestant Reformation by checking out the resources at the Colson Center online bookstore. One great suggestion is Eric Metaxas’s latest book “Martin Luther: The Man Who Rediscovered God and Changed the World.” Get your copy now. And listen to the podcast of John talking with Eric about Martin Luther, the Reformation, and the modern world by clicking here.