By Daniel Burke, CNN

(CNN) -- With police tape marking the barriers of their makeshift congregation, members of this city's grieving Jewish community welcomed the Sabbath outside of the Tree of Life Synagogue on Friday evening, an emotional act of worship and defiance just six days after the synagogue witnessed the worst anti-Semitic attack in American history.

About 50 men locked arms and swayed, harmonizing in Hebrew under darkening skies, while police looked on and pilgrims laid stones and flowers at memorials for the 11 congregants who were slain last Saturday. The building is still closed while police process the crime scene.

Many of the women sang, too, though they stood off to the side, a separation common in the more conservative branches of Judaism. Children ran back and forth playing between their parents' legs. A father gently wiped tears from his teenage son's cheeks, consoling him softly as the congregation prayed.

At one point, the service was stopped to thank a member of the FBI who had helped the Chevrah Kadisha, the Jewish organization that helps prepare bodies for burial. Afterward, the congregation broke into "Al Hanisim," a Hanukkah song that commemorates Jews' perseverance in the face of violent oppression. Though not normally a part of Shabbat services, no one had to ask why the song was appropriate to sing on this night.

"The Jewish people know from our history that, no matter how bad things seem, we can always pull together, we will always persevere," said Rabbi Sam Weinberg, principal of the Hillel Academy of Pittsburgh, whose students helped organize the Shabbat service through text messages on Friday.

"Six days after, right here," he continued, pointing at the Tree of Life Synagogue that loomed nearby, "the most horrible and terrible thing happened, we can still come together as a people and recover a little bit of the peace of Shabbat."

The service, one of many held across the city, capped an emotional day in Pittsburgh, as the city's Jewish community buried the last of their dead. As night fell, it seemed as if half of Squirrel Hill, Pittsburgh's historically Jewish neighborhood, was walking home from Sabbath services, huddling together against the cold.

'A circle no one wants to be a part of'

The last funeral for the 11 Jews killed six days ago was held Friday. Rose Mallinger, 97, was remembered for her strong will and commitment to Tree of Life.

Under the soaring vaults of Rodef Shalom's sanctuary, Mallinger's family and friends praised her zest for life.

"She was 97, but she was not done," said Rabbi Jeffrey Myers, who led Mallinger's congregation at Tree of Life/Or L'Simcha. "She had spunk."

Later in the service, Myers said that "an angel" had visited him Friday morning, just as his spiritual strength was waning. That angel, he said, was the Rev. Eric S.C. Manning, pastor of Emanuel African Methodist Episcopal Church in South Carolina, where a gunman killed nine members in 2015.

Wearing a button commemorating the Charleston massacre, Manning said he traveled to Pittsburgh on Friday to offer moral sustenance, show solidarity and to "pay it forward," after so many Americans stepped up to support his church.

At Mallinger's memorial service, the pastor read Psalm 23 and told the congregation that his church "mourns with you, is here with you and will always be here with you."

After the service, a long line of mourners waited to speak with Manning, hugging him and tearfully thanking him for coming to Pittsburgh.

Pittsburgh's Jews and his Charleston community share a common and tragic bond, Manning said in a brief interview afterward.

"We are part of a circle that no one wants to be a part of," he said. "What we have to do, today, and every day, is to make sure that that circle doesn't get any bigger."

Manning was just one of many people across the world moved by last Saturday's anti-Semitic attack.

Myers said he received a call from Israeli Prime Minister Benjamin Netanyahu on Friday. After a brief discussion about what language to converse in (Myers said they chose Hebrew, their "mother tongue") Netanyahu told him that all of Israel mourns with Pittsburgh, Myers said.

Outside Tree of Life, pilgrims gathered to place flowers and signs at the memorials for the 11 Jews killed by the gunman last Saturday.

Among them was Jody Yoken and her 9-year-old son, Ryder, who were in town from Toronto for a hockey tournament. Yoken said her son, who attends a Hebrew school in Canada, has asked difficult questions in the aftermath of Saturday's attack: Are we safe? Why don't people like us?

"I tell him that some people have difficulty accepting differences," Yoken said, "and that's why we have to try to be as accepting of other people as we can be."

A global outpouring

The Twitter hashtag #ShowupforShabbat has been trending all week, with communities in the United States urging people to attend synagogues and show their support in the aftermath of the attack.

In Britain, the mayor of London, Sadiq Khan, wrote on Twitter that he would attend synagogue on Saturday to stand "shoulder to shoulder with Jewish Londoners for their Shabbat service to show solidarity to the victims of the Pittsburgh shooting last weekend."

The UK Jewish community is also rallying to show solidarity, with leaders urging people to attend services Friday night and Saturday morning.