There are very few historical personalities with the magnetism of the famous Augustinian monk Martin Luther. Make no mistake, Luther has been praised and vilified. For some he bears specific blame for dividing the church. For others he remains a hero because he recovered the gospel and opposed massive church abuses. Love him or hate him, Martin Luther gets a response.

2017 marks the 500th anniversary of the Protestant Reformation. Some Protestants are aglow with celebration, while others would rather not talk about it. Catholics are more interested than ever, even open to new dialogue about some of Luther’s burning concerns. Pope Francis himself marked the anniversary October 31, 2016, with a historic trip to Lund, Sweden. He met with leaders from the Lutheran World Federation to celebrate a document titled: “From Conflict to Communion.” The document does not pretend to solve all the disagreements between Lutherans and Catholics. It does something more important by seeking forgiveness for our multiplied divisions. The pope and the Lutheran leaders look for greater celebration of our differing gifts while they long for a time when unity might reign in the midst of our amazing diversity.

Luther’s internal journey began with a deeply personal question that vexed his soul: “How can a sinner find mercy with a just God?” He discovered the answer in Romans 1:17: “The righteous live by faith.” God’s mercy alone was his only hope in life and in death.

Over the course of a dark and divisive political debate last year Americans are more polarized than ever. We have a traditional motto: E pluribus unum (“One out of many”). This saying has run through our society as an expression of great unifying force. We are the land of diversity united in the common pursuit of freedom. But something has happened in the last few decades. The unum (oneness) of America is disintegrating. My friend Cardinal Joseph W. Tobin spent two decades abroad before he returned to serve the diocese of Indianapolis. He says he found our American divisions “shocking and distressing.” I agree.

What do Luther, and the Catholic Church in the sixteenth century, have to teach us as we draw nearer to the precipice of social and religious demise? Throughout history the church has grown and declined. At times the influence of Christianity has shifted from one region, or continent, to another. But now our “shocking and distressing” divisions can be seen in our everyday life. There seems to be a harsh and persistent debate that marks us. We argue over politics, race, gender, marriage; and we still debate doctrinal issues that are neither confessionally essential or Christ-exalting. The sad legacy of Luther and the Reformation, with our resultant division, remains. But it seems now we are reaping what we have sown at a dizzying pace.

What should we work and hope for at such a time as this? Most of us know that elections do not turn cultures and churches into safe havens for love and charity. In the sixteenth century, when great moral and spiritual darkness covered Europe, the words Job 17:12 reminded many that the light would always be found nearest to darkness. The Latin phrase Post tenebras lux (Light After Darkness) became a Calvinist motto in Geneva. This idea was subsequently adopted by the entire Protestant Reformation. The Reformers believed the gospel was the light that would arise in the midst of pervasive darkness.

Through five centuries the church, both Catholic and Protestant, has experienced great times of gospel transformation when the good news has changed people and cultures. Luther’s great vision of mercy has, at our best moments, overcome the darkness of our divisions.

The signs of our times call for a recovery of God’s mercy. We need the light of the gospel, not more division.

Luther can again be a model, for both Catholics and Protestants. He is right: only God’s mercy can heal us from deep wounds. The pressing questions remain: Where can we find mercy for today and bright hope for tomorrow? The answer is exactly where Luther found it, in the good news. God’s mercy can heal our hearts, restore our love, transform our homes, rebuild our churches and visibly unite us in the love that leads us to serve our neighbors. Could the divisions of the sixteenth century actually lead us to fresh discovery of unity in the twenty-first century, a unity rooted in God’s mercy? I pray so.