The waffle vendor around the corner is doing brisk business as hundreds of tourists stream down the cobbled alleys of this ancient Belgian town. His sweet creations, individually dipped in chocolate and pistachio—each mounted on a stick—are carried triumphantly by pilgrims headed toward the square where the rock band is warming up.

Guttural throbs from an electric bass reverberate in this medieval quadrangle, raucously incongruous in a place bedecked with symbols of gentility and wealth. Tonight 10,000-watt amps will be loosening the mortar on a dozen aging structures.

At 2:00 p.m. the pilgrims take their final hasty bites and solemnly enter the Basilica of the Holy Blood, a twelfth-century chapel containing the region’s most sacred relic. Tradition says that the clear crystal cylinder preserves the blood of Jesus, caught by Joseph of Arimathea as he helped entomb the dead Saviour.

“The movement now celebrating its half millennium is increasingly akin to the one that Martin Luther, John Calvin, and John Knox protested.”

Dozens of the faithful line up to mount the white marble altar on which the reliquary rests, each carefully placing their hands on the clear glass panel above the venerated blood. Some linger for a moment, deep in prayer; others glide with the practiced pace of those intent on keeping their itinerary.

Five minutes after ringing the bell and urging veneration of the relic, the robed young priest who spoke so movingly is changed into a flannel shirt and corduroys, selling postcards in the gift shop.

It is temptingly easy for a Protestant like me to scorn the crass commercial culture that mingles waffles, Pink Floyd, and the blood of Jesus without a hint of irony—as if the life of faith could be so neatly compartmentalized. The errors of another’s cultural religion—the specks (or spectacles) in another’s eye—are easier to spot than the well-worn plank obscuring my own eyesight.

This October, what remains of Protestantism will celebrate 500 years since Martin Luther nailed his arguments to the door of the Castle Church in Wittenberg. Thousands of PowerPoint presentations will image the tonsured priest, hammer in hand, to megachurches everywhere, while worship bands search hymnals for that venerable relic Luther penned—“A Mighty Fortress.” Much will be said—and some of it heard—about sola scriptura and salvation by faith. And then 170 million North American Protestants will hurry home to munch fried chicken and thin pizza while waiting for the Bears to maul the Saints.

The differences separating Protestants from Rome are still real enough in doctrine and theology, despite a century of overtures and undertones about a grand reconciliation to reunite what the Reformers divided. The fundamental biblical distinctions about how lost human beings are saved—trusting only in the merits of Jesus; unaided by the good we sometimes do; without the intercession of the saints—remain, unaltered by the passing of centuries.

But culturally the movement now celebrating its half millennium is increasingly akin to the one that Martin Luther, John Calvin, and John Knox protested. The truths for which 50 million martyrs died are now curious relics in many churches, replaced by softly styled worship songs comparing Jesus to new love. We take our faith in bite-sized pieces now—religion on a stick—all interspersed with cultural “norms” that biblical Protestantism should make us reconsider, and reform.

Where is the protest when the gospel of prosperity is welcomed in so many congregations? And where the cry when “optimism” and “positive thinking” replace the preaching of the cross? Where do we find a true, reforming spirit—challenging the accepted (and unbiblical) day of worship; questioning the doctrine of eternal torment; plainly stating that the dead await the coming of the Lord? Who raises the alarm when militant Christians use the power of civil government to enforce their angry views on justice, warfare, and the sacred freedom of minority religions?

I know one faith that, in its core, is still supremely Protestant. It is the faith to which, through grace, I have been called to faith, and even to minister the everlasting gospel, heralded by angels.

So here I stand; I can do no other. So help me God.