“The Bible was taken and used as a manuscript for conformity and we want to turn it into a manifesto of creativity,” he said after a recent sermon. “We want, whenever someone hears the name Jesus, to go: ‘Oh. Creativity, beauty, imagination, wonder,’ instead of, ‘Rules, laws, conformity, judgment.’”

LOS ANGELES — Just before 10 a.m. on a sunny Sunday in November, a crowd gathered in front of a white modernist building here on Hollywood Boulevard. An inscription on its side, “H/N,” short for “Here and Now,” stood out from a

Twenty- and 30-somethings spilled onto the steps and the lawn, dressed in crop tops, moto jackets, and jeans torn deliberately at the knees.

“How was your party last night?” a young woman in a shirt dress and bootees asked a guy in aviator sunglasses and a swath of chains. “I heard it was amazing.” He replied: “Girl, can you stop losing weight? You’re going to disappear.”

They sought not physical but spiritual nourishment. The building? Mosaic, a church that counts thousands of young people among its congregants, offering sermons rife with pop-culture references, musical performances that look like Coachella, and a brand cultivated for social media. (Church events are advertised on Instagram; there’s a “text to donate” number).

While Christianity is on a decline in the United States, at Mosaic and other churches like it in the Los Angeles area, the religion is thriving.

“We have a hundred people every week who come to faith in Jesus,” Erwin McManus, Mosaic’s founder and lead pastor, said after the first of four services that Sunday.

This being Hollywood, famous faces are among the faithful. Joe Jonas has been to Reality LA, a new-age church in Hollywood that meets in an unadorned high school auditorium. (There, congregants send prayer requests via text messages.) Viola Davis is a regular at Oasis, a neon-hued service inside a Koreatown cathedral. Justin Bieber supports Hillsong.

But Mr. McManus, 57, insists that his congregants are there for the message, not celebrity-gawping or networking. “This isn’t sanitized,” he said. “This is not Jesus-lite.”

Services start with music from a live band, their lyrics projected onto a giant screen. Lit by multicolored spotlights, they bring the crowd to its feet, hands in the air.

A few singers take turns leading songs, most of which are originals that praise God’s glory. Mr. McManus’s daughter, Mariah, 23, is a regular frontwoman, belting out breathy “hallelujahs” on a recent Sunday to a packed house of over 700 people.

After a half-hour, Mr. McManus emerged onstage dressed in black skinny jeans, black leather high-top sneakers and a long black T-shirt, his hair slicked back in a trendy undercut style. He could easily have passed for a pop star swanning through the doors of the Chateau Marmont. In fact, one of the early iterations of Mosaic, back in the ’90s, was held in a Los Angeles nightclub owned by Prince.

“I thought it was kind of iconic,” Mr. McManus said. “It was really nasty. I wanted to take what people considered to be a safe haven to the most profane space possible.”

Born in El Salvador, Mr. McManus grew up with a variety of religious influences: His maternal grandmother was Roman Catholic, his mother Buddhist and his father Jewish. He studied philosophy and psychology at the University of North Carolina, Chapel Hill, and at 20 decided to follow the word of Jesus. He went on to receive a master’s in divinity from Southwestern Theological Seminary.

Soon after, he moved to Los Angeles to work as a futurist and found himself helping friends, as he put it, “come to faith.” He had an epiphany at a screening of “Braveheart,” watching Mel Gibson’s character rally his troops for battle.

“I had this visceral response and I thought to myself, ‘I can’t let the most meaningful moment of my life be watching a movie,’” Mr. McManus said. “Sunday needs to feel like this. You go to church on Sunday and you don’t have any sense of the heroic. We have a really powerful heroic narrative here, of the extraordinary good you can do in the world.”

The nightclub gathering expanded into a network of nontraditional churches throughout Southern California that grew so big that in 2009, Mr. McManus stepped away. “I didn’t want to manage it,” he said.

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