Despite the rain, 83-year-old Mabel Cooper got out of the van at 27th and Dumbarton streets NW to hold the door for her sister and others heading into First Baptist Church of Georgetown on a Sunday early this month.

Moments later, deaconess Rebecca Sims began the adult class in the main sanctuary, teenagers nibbled on pastries in a Sunday school class in the basement and Carol Butler and other women put the final touches on a celebratory meal in the kitchen.

For Cooper and her 85-year-old sister, Mary Davis, there was no time to waste. They stationed themselves in the vestibule and folded programs to give to people as they entered the historic African American church to celebrate its 150th anniversary.

“We always try to greet people with a smile,” Cooper said.

Standing next to Cooper, Davis added, “This is the Lord’s work.”

From the processional hymn, “We’ve Come This Far by Faith,” to the closing hymn, “I Thank You Jesus,” the songs chosen for the service were all about gratitude. In his message, the Rev. Robert K. Pines compared the 130-member church to a ship of Zion that has weathered many storms.

“This church didn’t get here without getting through deep waters,” Pines said. “God uses deep waters to drive us, drive us to our knees. God uses deep waters to drive us to our destiny. God uses deep waters to push us to perfected praise.”

Two days before, members of the small congregation had attended a banquet at the Joint Base Myer officers’ club in Virginia, where ministers from across the area reflected on the legacy of the church, which was founded by a former slave, the Rev. Sandy Alexander, during the Civil War.

Lorraine Smith, chairman of the 150th anniversary committee, said it was proper to cross the river for the banquet, because at one time both banks of the Potomac between Georgetown and Rosslyn were occupied by communities of black families. Descendants of the original members are well represented in the First Baptist congregation.“My family has been here since the inception of the church,” Smith said as she pointed to a photo on a church wall of her great-great-great-grandparents Spencer and Dorothy Coleman. Then she pointed to a photo of a little girl and said, “That is my grandmother.”

According to church history, Alexander and his wife came to Georgetown from Fredericksburg in 1856. They started holding church meetings in private homes blocks from the church’s current location. In 1882, the cornerstone for the church was laid. According to Anita Flemming, chairman of the church’s historic archives committee, from the very beginning members were proud of their role in forming the first Baptist church in Georgetown.

“When the trustees made the first payment on the note, the bank made the receipt to the First African Baptist Church, and trustee William Brown refused to accept it,” Flemming said. “The receipt was torn up, and he insisted that he represented the First Baptist Church of Georgetown.”

During the banquet, the Rev. Robert Cochran, an official of the D.C. Baptist Convention, recognized the church as the first Baptist congregation in Georgetown. He also noted that the congregation was founded before President Abraham Lincoln issued the Emancipation Proclamation freeing the slaves. “Rev. Sandy Alexander was a man of vision,” Cochran said. “He knew that people would be coming to Washington, D.C., and would need the Gospel of Jesus Christ.”

Under the leadership of a dozen pastors, the church grew, but it remains primarily a family church and members who have moved to Maryland and Virginia return on Sundays to worship.

Butler, a trade association executive who lives in Northwest, was serving chicken and dressing at the meal after the 150th anniversary service. She said she feels compelled to volunteer at the church because that was what her mother, grandmother and great-grandmother did.

“My mother was president of the usher board, and when they had an event, this was where she was,” Butler said. She said that as she grew older, she began cooking with her mother. “I would make the macaroni and cheese,” Butler said, “and she would make the sweet potato pies.”

Because the congregation is small, many people do double duty. For example, Frank L. Bailey, chairman of the deacon board, also sings in the choir under the direction of his wife, deaconess Louella Bailey, who is also the church’s minister of music.

During the meal after church, Pines and Frank Bailey listened attentively as the older women of the church, including Vera Jones Frazier, 91, talked about Georgetown and the church back in the day.

“I was born in Columbia Hospital, and when we started coming to this church, the M Street bridge was wooden,” Frazier said.