In the old city of Geneva, Switzerland, there’s a lovely park adjacent to the University of Geneva, close to the church where John Calvin preached and taught daily. The park contains a lasting memorial to the 16th-century Protestant Reformation. The central feature is a magnificent wall adorned with statues of Calvin, John Knox, Huldrych Zwingli, Theodore Beza, and others. Chiseled into the stone are the Latin words Post tenebras lux (“After darkness, light”).

These words capture the driving force of the Reformation. The darkness referred to is the gospel’s eclipse in the late Middle Ages. A gradual darkening reached its nadir, and the light of the doctrine of justification by faith alone was all but extinguished.

Fuel for Fire

The Reformation firestorm was fueled by the most volatile issue ever debated in church history. The church had faced severe crises in the past, especially in the fourth and fifth centuries when the nature of Christ was at stake. The Arian heresy of the fourth century culminated in the Council of Nicea and the Nicene Creed. The fifth century witnessed the church’s struggle against the monophysite and Nestorian heresies that resulted in the Council of Chalcedon’s clear declaration of the humanity and deity of Christ. Since Nicea and Chalcedon, the ecumenical decisions of these councils have served as benchmarks for historic Christian orthodoxy. The doctrines of the Trinity and the union of Christ’s divine and human natures have since been regarded, almost universally, as essential tenets of the Christian faith.

Every generation throughout church history has seen doctrinal struggles and debates. Heresies of every conceivable sort have plagued the church and provoked fierce argument, even schism.

But no doctrinal dispute has ever been contested more fiercely or with such long-term consequences as the one over justification. There were other ancillary issues debated in the 16th century, but none so central or so heated as this.

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