It isn't easy being Reformed on Madison Avenue. Just ask Presbyterian pastor and former Westminster Seminary professor Tim Keller. Four years ago, despite the difficulties, he planted a church in midtown Manhattan, and today Redeemer Presbyterian Church effectively reaches students, office workers, corporate executives, and intelligentsia.

Keller's office, on the twelfth floor of a Madison Avenue high-rise, is wedged between the skyscrapers of New York's famous skyline. And just a five-minute cab ride from the office, the congregation meets for worship three times each Sunday in the auditorium of Hunter College. Its 11:00 a.m. service, rich in liturgy and classical music, attracts a crowd as ethnically and spiritually diverse as any Broadway musical. Its 6:30 p.m. contemporary service could be mistaken for a Broadway musical.

That contrast prompted Leadership Journal editors Dave Goetz and Marshall Shelley to brave the January slush one Sunday to worship there. At ten minutes ...