President Obama spoke in rememberance of the three victims of the Boston Marathon bombing and praised the resilience of the city of Boston at an interfaith service on Thursday. (The Washington Post)

President Obama extended the nation’s solidarity to a city still aching from Monday’s twin bombings at the Boston Marathon, meeting injured patients and family members Thursday afternoon and telling a packed cathedral prayer service that “Boston’s your home town, but we claim it a little bit, too.”

Many in the audience at the interfaith prayer service in the soaring Cathedral of the Holy Cross in the city’s South End dabbed at tears as the president eulogized the three young spectators who were killed when shrapnel and shockwaves blasted through the cheering multitude near the finish line. And audience members nodded agreement as he encouraged the dozens who were injured.

But Obama stirred his listeners most when he cited the city’s grace and grit and generosity as examples of the best of America.

“Every third Monday in April, you welcome people from all around the world to the Hub — for friendship and fellowship and healthy competition,” he said, referring to the city’s beloved marathon, which was founded 117 years ago.

Turning the marathon to a metaphor for perseverance in life, he continued, “Even when our heart aches, we summon the strength that maybe we didn’t even know we had. We finish the race.”

His next words were nearly drowned out by applause as most of the 2,000 listeners rose to their feet: “And this time next year, on the third Monday in April, the world will return to this city and run harder than ever, and cheer louder than ever, for the 118th Boston Marathon. Bet on it.”

It was meant to be a day of continued physical and emotional healing, and the the theme of the prayer service was just that: Healing Our City. The president was accompanied by First Lady Michelle Obama.

Among others in the cathedral were family members of Krystle Campbell, a 29-year-old restaurant manager from Medford, Mass., who was killed. Obama met with the family before the service.

Also present were more than a dozen teachers and administrators from the Neighborhood House Charter School, where 8-year-old Martin Richard was in the third grade. He was killed and his mother and younger sister remain hospitalized. The girl, in the first grade, lost a leg, according to a school official.

“I think just the president remembering Martin and offering prayers for the recovery of his sister and his mom, that helped a lot,” said Dominic Slowey, a school spokesman. “The prayer service is part of the healing process for the school.”

The other fatality was a 23-year-old graduate student from China, Lu Lingzi.

People began gathering outside the church shortly after midnight to get free tickets and many attendees said they felt the same sense of balm and comfort.

“It was one great motivational speech after another,” said Chief Jim Hooley of Boston Emergency Medical Services, who treated injured spectators at the bomb scene. “At the end, with the president, you felt like you were at a revival meeting, and you just wanted to get back out there to work.”

“We, as a city, have along way to go to heal, and it really helps to know we have this much support,” said Barbara Ferrer, Boston’s public health commissioner.

“That speech he put together.” said Daniel Johnson, clinical nursing director at Tufts Medical Center, which admitted 18 bomb blast patients, referring to Obama’s seeming personal feel for Boston. “I feel so much better. I’ve been on edge. I’ve been up a couple night. I’ll sleep better tonight.”

The service included reflections offered by Christian, Jewish and Muslim faith leaders, including Cardinal Sean O’Malley. The cathedral is the “mother church” of the Roman Catholic Archdiocese of Boston, a city with a strong Catholic tradition.

The gospel reading was the Sermon on the Mount from the Book of Matthew -- “Blessed are those who mourn.” The pastors wrestled with the concept, described by Rev. Liz Walker from Roxbury Presbyterian Church, of “how can a good God allow bad things to happen?”

The partial answer they seemed to settle on was the miracle of Boston’s response to the tragedy -- the bravery of rescuers dashing into danger, the kindness of everyday Good Samaritans, the love of families in distress.

Massachusetts Gov. Deval L. Patrick (D) and Boston Mayor Thomas M. Menino each spoke emotionally to the gathering.

“We will recover and repair. We will grieve our losses and heal. We will rise and we will endure,” Patrick said. “We will have accountability without vengeance. Vigilance and not fear. And we will remember, I hope, long after the buzz of Boylston Street is back . . . that the grace this tragedy exposed is the best of who we are.”

Menino, his voice choked with feeling, talked about the resilience of the city he has led since he was elected to the first of five terms in 1993 and the love he feels for its citizens.

“We love the brave ones who felt the blast and still raced into the smoke. This was the courage of our city at work,” said Menino, who is recovering from leg surgery unrelated to the bombing and grimaced in pain as he rose from a wheelchair to stand in the pulpit. “We love the fathers and the brothers who took shirts off their backs to stop the bleeding. The mothers and the sisters who cared for the injured. The neighbors and the business owners . . . that opened their doors and their hearts to the weary and the scared.

“They said, ‘What’s mine is yours, we’ll get through this together.’ ”

The pews were filled with doctors, nurses, first responders, runners, marathon volunteers, out of towners and politicians including four former governors of Massachusetts, among them 2012 Republican presidential nominee Mitt Romney.

“We’re here to support the victims, to support Boston,” said Karen Richards, 50, from the San Francisco Bay area, who attended wearing a blue marathon jacket. She had just finished running the race when the bombs went off.

Richards’s friend Cheryl Babel, 58, a teacher from the Bay area, was stopped by police a half mile from the finish, after the blasts.

“We were all in a safe place -- we’re just here to support those who were not fortunate enough to be in a safe place,” Babel said.

Lisa Evans, 51, a retail analyst who was at the race to cheer on Richards and Babel, said the service will help her begin to process the episode.

“It was everybody who experienced that coming together in one room, instead of trying to figure it out on their own,” she said.

The Boston Children’s Chorus performed the Patty Griffin folk song “Up to the Mountain,” accompanied by famed cellist Yo-Yo Ma and other musicians. As they sang, several young chorus members fought back tears.

The president and the first lady flew to Boston on Air Force One. They were joined by the state’s two Democratic senators, Elizabeth Warren and Mo Cowan, and members of its congressional delegation. Vicki Kennedy, wife of the late Sen. Edward M. Kennedy, also attended.

Following the service, Obama went to nearby Cathedral High School, where he addressed hundreds of marathon volunteers and officials of the Boston Athletic Association, which organizes the marathon.

The main message, Obama said, was “to say how proud the whole country is of you.”

He next went to Massachusetts General Hospital where he met with medical staff and patients injured in the bombings.

Obama’s words to the patients in their hospital beds were private. But he gave a sense when he addressed the in absence at the church: “Know this: As you begin this long journey of recovery, your city is with you. Your commonwealth is with you. Your country is with you. We will all be with you as you learn to stand and walk and, yes, run again. Of that I have no doubt. You will run again.”

Wilgoren reported from Washington.

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