Obama described how his own beliefs were grounded in his mother's spirituality and deepened through his career in public service. His faith, Obama told the gathering of lawmakers and religious leaders, has sustained him during the trials of the presidency, including when he hears that faith "questioned from time to time."
"We are reminded that ultimately what matters is not what other people say about us, but whether we're being true to our conscience and true to our God," he said.
The president began his remarks by acknowledging Mark Kelly, the husband of Arizona Rep. Gabrielle Giffords, saying that "we are with them for the long haul, and God is with them for the long haul." Kelly attended the service as his wife continues to recover from the January shooting at a constituent-service event in Tucson.
Obama also briefly addressed the crisis in Egypt, saying: "We pray that the violence in Egypt will end, and that the rights and aspirations of the Egyptian people will be realized, and that a better day will dawn over Egypt and throughout the world."
But most of his remarks were deeply personal. He talked of his father, a "nonbeliever" who he met just once. His mother grew up "with a certain skepticism about organized religion," and rarely took him to church. Yet she "was also one of the most spiritual people that I ever knew," he said.
"She was somebody who was instinctively guided by the golden rule and who nagged me constantly about the homespun values of her Kansas upbringing, values like honesty and hard work, and kindness and fair play," he said. "And it's because of her that I came to understand the equal worth of all men and all women, and the imperatives of an ethical life, and the necessity to act on your beliefs."
The fact that Obama has rarely attended religious services has been a source of controversy. An August 2010 Pew study found that only one-third of Americans identified Obama as Christian, and 43% said they did not know his faith.
On Thursday, Obama spoke of the value of prayer, saying, "Let me tell you, these past two years, they have deepened my faith." He talked of the daily meditations he receives from Joshua DuBois, head of his faith-based initiatives office, the occasional visits from pastors to pray with him in the Oval Office, and the "respite and fellowship" of the chapel at Camp David.
"When I wake in the morning, I wait on the Lord, and I ask him to give me the strength to do right by our country and its people," he said. "And when I go to bed at night, I wait on the Lord, and I ask him to forgive me my sins and look after my family and the American people and make me an instrument of his will."
After the breakfast, Obama is set to head to Penn State University for a speech on innovation and clean energy. He's scheduled to announce a new "Better Buildings initiative" to help the private sector invest in renovations to make facilities more energy-efficient.