The historic black church in Charleston, S.C, held its first worship service since nine of its members were killed during a Bible study Wednesday night.

Emanuel African Methodist Episcopal church was filled for the service Sunday morning. Uniformed police officers are posted on both levels of the sanctuary.

The service started with a message of love, recovery and healing, which will no doubt reverberate throughout churches across the country.

"We still believe that prayer changes things. Can I get a witness?" the Rev. Norvel Goff said. The congregated responded with a rousing "Yes."

"But prayer not only changes things, it changes us," Goff said.

Goff is a presiding elder of the 7th District AME Church in South Carolina. He was appointed to lead the historic Charleston church after Senior Pastor Clementa Pinckney was shot and killed. He will remain at the church until a new pastor is named.

"It's been rough," Goff said. "We some of us have been downright angry.""But through it all, God has sustained us and encouraged us. Let us not grow weary."

Goff vowed that he and others will "pursue justice and we're going to be vigilant and we are going to hold our elected officials accountable to do the right thing."

Authorities say a young white man, Dylann Roof, opened fired at the church in a racially motivated attack. He was arrested a day later.

A friend of Roof's told The Associated Press the gunman's original target was the College of Charleston, but he may have been dissuaded by the fact that the school has a police department that patrols the downtown campus.

"I don't think the church was his primary target because he told us he was going for the school," said Christon Scriven, who had dismissed Roof's threat as drunken bluster. "But I think he couldn't get into the school because of the security ... so I think he just settled for the church."

Roof had a bond hearing on Friday. Some victims' families spoke to him then, offering him forgiveness and mercy.

Events to show solidarity are planned throughout the city and beyond. At 10 a.m. ET, church bells rang throughout downtown this "Holy City" — which garnered the nickname because of the numerous churches here.

At the Arthur Ravenel Bridge, people are expected to gather and join hands in solidarity.

One of those who showed up on Sunday evening was 58-year-old accountant Sherry Howard of Moncks Corner. Howard said she drove 45 minutes to attend.

Asked why she came out, she said: "One reason is for unity. And another reason is to show that even though we are hurting and we're broken now, we are of one accord."

The shooting was a tragedy, "but out of that tragedy, look what came about: love," she said, gesturing toward dozens of people who were walking toward the gathering point.

The bridge is named after a former state lawmaker and vocal Confederate flag supporter. The slayings have renewed calls for the flag to be removed from the South Carolina Statehouse grounds, in part because photographs of Roof in a purported manifesto showed him holding Confederate flags.

South Carolina Gov. Nikki Haley and Mayor Joseph Riley attended the service at Emanuel.

Despite the grim circumstances the congregation has been faced with, the welcoming spirit Roof, 21, exploited before the shooting is still alive, the church members said.

Harold Washington, 75, expects the sanctuary to host even more newcomers after one shattered the group’s sense of peace and security.

"We're gonna have people come by that we've never seen before and will probably never see again, and that's OK," he said Saturday. "It's a church of the Lord, you don't turn nobody down."

Church leaders will try to address the heavy psychological burdens parishioners bring with them.

"I think just because of what people have gone through emotions are definitely heightened, not just in Charleston but with anyone going to church because it is such a sacred place, it is such a safe place," Shae Edros, 29, said after a multiracial group of women sang "Amazing Grace" outside the church Saturday afternoon.

"To have something like that completely shattered by such evil -- I think it will be in the back of everyone's heads, really," Erdos said. Erdos was planning on attending Sunday service in nearby Mount Pleasant.

The suburb is connected to Charleston by the Arthur Ravenel Bridge, where people are expected to join hands in solidarity Sunday evening. The bridge’s namesake is a former state lawmaker and a vocal Confederate flag supporter. Roof had been photographed with the flag several times before the shooting.

The Rev. Ed Kosak of the Unity Church of Charleston said delivering Sunday morning’s sermon would be emotionally taxing but he felt empowered by the strength and grace Emanuel members have shown – a demeanor he said has set the tone for religious leaders everywhere.

"I've gone into Sunday sermons before like when Virginia Tech happened, and when the Sikh shootings happened" Kosak said. The situation in Charleston may be harder to give a sermon on because it hits so close to home. But, Kosak said, "I am more ready than ever to speak to this tragedy in ways I didn't think I could before."

For the family of Cynthia Hurd, Sunday’s service will be especially poignant. The longtime librarian would have been celebrating her 55th birthday and was planning a trip to Virginia with her siblings.

"Sunday will not be a sad day for me; it will be a celebration for me. It will be a celebration for our family because our faith is being tested," Hurd's younger brother Malcolm Graham said Friday. "She was in the company of God trying to help somebody out. She was where she needed to be."

Felicia Breeland, an 81-year-old lifelong Emanuel member, said she sang in the choir with Susie Jackson, 87, who was also fatally shot Wednesday.

"It's going to be sad. She sits right on the front row, too," Breeland said. "She had a very soft soprano voice. It was beautiful."

Washington said he expected a tearful, emotionally charged gathering.

"I hope we'll be much stronger. I think we will because it brings people together. For how long? I'm not sure. But at least for right now we're very well galvanized," he said. "We didn't miss a Sunday."

The Associated Press contributed to this report.