When Pastor Tullian Tchividjian was tapped to become the next senior minister of the historic Coral Ridge Presbyterian Church in Fort Lauderdale, Florida, the world of media was quick to note obvious differences between him and the megachurch’s founding pastor, the late Dr D James Kennedy.

Tchividjian “cuts a far different image”, noted a reporter for The Associated Press.

“His hair is spiky, his beard sometimes scruffy, his skin tan,” the reporter added.

Being only 36, Tchividjian may look like the typical trendy and modern pastor of today who would try to make his church more relevant and more appealing to draw the unchurched. But he is among those Christian leaders who believe that the main problem churches face is not that they are culturally out of touch, but that they are theologically out of tune.

“We need to remember that God has established his church as an alternative society, not to compete with or copy this world, but to offer a refreshing alternative to it,” Tchividjian writes in his recently released book, Unfashionable: Making a Difference in the World by Being Different.

“When we forget this, we inadvertently communicate to our culture that we have nothing unique to offer, nothing deeply spiritual or profoundly transforming. Tragically, this leaves many in our world looking elsewhere for the difference they crave,” he adds.

For Tchividjian, whose grandfather is the renowned Rev Billy Graham, what drew him back to church after years of chasing the things of the world was his encounter at the age of 21 with the “radical difference” he had been longing for.

“I was a seeker being reached, not by a man-centred, trendy show, but by a God-centred, transcendent atmosphere,” he recalls.

The Jacksonville-born preacher is convinced that serious seekers today aren’t looking for something appealing and trendy.

“They’re looking for something deeper than what’s currently in fashion,” Tchividjian insists.

Through Unfashionable, the south Florida pastor makes the case for Christians to make a difference in the world by being different from the world. He explains what it means to be out of style in the culture, to pattern ideas, beliefs, methods and tastes in alignment with God’s ways and not the world’s.

He also makes a passionate plea for Christians to stop trying so hard to be cool, to fit in, and instead be courageous enough to be different.

“Truthfulness, not trendiness is what new generations are thirsting for,” Tchividjian writes. “They want to know there are people out there with their sights set on a different world.”

Tchividjian hopes to mobilise a generation of God-saturated missionaries who will “live against the world for the world” and not be “seduced by cool” or what’s fashionable.

To date, Tchividjian’s new book has received praise from prominent American Christian leaders including Mark Batterson, lead pastor of National Community Church; Chuck Colson, founder of Prison Fellowship; Ed Stetzer, president of LifeWay Research; and Kevin DeYoung, pastor of University Reformed Church.