On Sunday mornings, Friendly High School becomes Ebenezer AME Church.

Worshipers stream through the double steel doors of the Fort Washington school, past the sign warning all visitors to report to the principal's office, into the auditorium where a large white cross is set against maroon velvet curtains. An open Bible rests on the makeshift altar. The congregation stands as choir members march down the aisle, clapping hands and singing in loud, soaring voices, "I just want to thank you, Lord, you've been so good to me."

The service, a two-hour affair, is held not once but twice on Sunday mornings. Otherwise, it would be impossible for Ebenezer's pastor, the Rev. Grainger Browning, to preach to his congregation of nearly 3,000 -- a congregation that numbered just 17 less than five years ago.

Ebenezer -- "The Family Church Serving the Family of God" -- is the most dramatic example of a recent explosion of growth that is forcing many black churches in Prince George's County to add services, use closed-circuit television to address an overflow of worshipers, and build million-dollar sanctuaries. The growth is, in part, a reflection of Prince George's continuing role as the suburban mecca for black middle-class families in the Washington area. Already the black population is 46 percent -- but church leaders say their growing congregations also indicate the rediscovery of religion as an antidote to hectic, pressure-packed lives.

"Ebenezer is sort of a miracle church because it grew so fast," said the Rev. Ernest Gibson, executive director of the Council of Churches of Greater Washington, which includes 547 churches of 17 denominations. "But churches in general -- and particularly black churches -- are growing. The way young people tell it, something is happening in the church right now."

Ebenezer's growth has come at an astounding rate. Just five years ago, the church left Georgetown, where it was founded in 1856, and moved to southern Prince George's with 17 members. Since then, the membership has grown to more than 2,800, including 900 teen-agers and children. The church organizations have grown from three to 50, including drug ministries, crisis counseling, tutoring classes and nine choirs. And, perhaps most telling, the weekly collection of offerings has grown from $150 to more than $19,000.

"We believe in a service of celebration," said Browning, 35, a bearded Howard Divinity School graduate whose wife Joann is the church's assistant pastor. "We want you to enjoy church, to be excited about coming to church; Jesus makes you feel good. And prayerfully, we minister to your needs and you tell a coworker and then they come, too."

Although overall statistics are not available, it is obvious that, in varying degrees, other predominantly black churches in the county also are bursting with new members: Union Bethel AME in Brandywine, which has doubled its membership in the past year, is planning a $1 million sanctuary to seat 500 people. In Oxon Hill, St. Paul United Methodist Church, which welcomed 100 members last year, is constructing a $3 million building. In Landover, Shiloh Baptist Church has grown in 10 years from 100 members to 1,200. During each of the two Sunday worship services, 150 people must watch what is taking place on closed-circuit television in the church basement, and the pastor, the Rev. Paul P. Pitchford, makes sure he goes downstairs "to tell everyone hello" at least once each service.

"What's happening out there in the world is crazy -- drugs and crime and people shooting police -- and you can't solve it yourself," said the Rev. John W. Johnson, pastor of the First Baptist Church of Glenarden, which began two worship services in 1975 and has about 700 members.

"It boils down to this," said Birthenia Sires, a federal government employee in her late thirties whose family recently joined Union Bethel Church. "You just need something to help you get through the week."

At Ebenezer Church, Grainger and Joann Browning quickly discovered that helping their suburban congregation get through the week requires a somewhat different approach to the ministry. Most of their members are government employees, teachers and business owners with an average annual income of about $30,000 -- not a group with the same immediate concerns as a low-income, heavily unemployed congregation.

"At first we thought we'd start a clothing closet for our members who needed clothes," Grainger Browning said in a recent interview at the church. "We had a big stack of clothes and people weren't coming to get them." The unclaimed clothes were eventually donated to an agency that helps the needy.

"Here, the message I preach is not so much that you can be somebody. It's more empowering," Browning said. "In this society, if you have an education and you wear nice clothes, then you feel your life should be happy. But things do not satisfy. You can have professional success and still not be satisfied.

"I also preach that you have a responsibility to the community, especially for those who are not blessed. God has given you the material -- not just for your own comfort, but so that you can assist others. If you graduated from a black university, for example, you should think about contributing back . . . ."

Although Ebenezer's Sunday morning services are held at Friendly, the church has a brick, stone and glass building on Allentown Road that houses its offices and is the site of all choir practices and meetings. The sanctuary, with dark wooden pews and blue stained glass, was outgrown two years ago and the Sunday worship transferred to Friendly, a few miles away. The area has an almost rural quality; across the street is Tony's Barber Shop and a 33-acre field where a 2,000-seat sanctuary will be built someday.

Such ambitious plans are a far cry from the Ebenezer Church of 1983. Then, the goal was simply survival. The black families that formed the church had long since moved from Georgetown, and the church building at 2727 O St. NW was in need of repair.

African Methodist Episcopal Bishop John Hurst Adams, noting the black migration to Prince George's, directed the purchase of the Allentown Road church, and encouraged other area AME churches to help with Ebenezer's monthly mortgage of $3,500. A month later, in June 1983, he appointed Browning to head the church -- which is Browning's first -- because "he had the kind of ministry and the personality to catch fire," Adams said.

By June 1984, Ebenezer had 500 members. By June 1985, a second service was added. A year later, the sanctuary at both services was packed, and several hundred additional worshipers were crowded into the basement and into a small chapel. It was time for the move to Friendly.

To increase interest in the church, the Brownings staged youth revivals, annual Superbowl fellowships and other get-togethers to which members had to bring nonmembers. Detailed campaigns were held "to win souls for Christ." A couple of appearances at the church by presidential contender Jesse L. Jackson also spread Ebenezer's reputation. Grainger Browning said that Ebenezer has failed to add new members on only two Sundays in five years -- and those were holiday Sundays.

"I never imagined we would grow so big," said Queen Clay, a D.C. public schools employee who with her husband, Melvin, was one of the original 17 members. "And it was hard at first to move, but we had the faith and we knew Ebenezer was fading away. I think we've grown so much because we really have a pastor who is God-sent. The way he preaches, a little child on up can understand."

The Brownings, both Boston natives, did not originally plan to enter the ministry. He had been a high school social studies teacher, she an administrator at Northeastern University, when he felt called to preach "out of the blue" and entered Howard in 1979. Joann Browning, 38, enrolled in divinity school several years later when she realized "I was using the excuse I had to pick Grainger up to sit in on his classes." Like many of the young professional couples who belong to the church, they have two children, Grainger III, 6, and Candace, 3.

Although it would seem that growing Prince George's churches such as Ebenezer are siphoning members from D.C. churches, it is not true that the inner-city churches are losing members in great numbers, church officials said. New members, they said, are joining all the time.

And, "even after they move away, people keep going to their family church for awhile. It takes that second or third generation to make the change," said Bishop Adams, adding that AME membership in Washington, Maryland, Virginia and North Carolina has increased from 60,000 to 100,000 in the past six years.

Browning said that although he was happy with Ebenezer's rapid growth, it has cost him much of the personal touch with his members that he once enjoyed.

"I used to call up every single family on Christmas Eve and tell them Merry Christmas," he said. "I guess it's a case of the classroom teacher becoming a principal -- and I love the classroom."

But for Tia Hastie and her friends, Ebenezer provides exactly the sort of personal attention they enjoy. Hastie, 16, said she participates in the church's pizza-movie nights, the ski parties and the "lock-ins, which are really these rap sessions where you stay up all night and really talk." She is proud of the fact that more than 100 of her schoolmates at Friendly have joined the church since its members began meeting at the school. And she says it doesn't bother her that the often-raucous school auditorium of her weekday life becomes her church on Sundays.

"Ebenezer means so much to me," said Hastie, who joined the church four years ago with her father, a retired military officer, her mother, a communications specialist, and her 14-year-old brother.

"The things the pastor talks about are the kinds of things we're going through, things that really relate to your life -- what to do about drugs and what to do with your future. It makes you want to come to church."