WASHINGTON — President Obama spent his first morning as president in a prayer service at the Washington National Cathedral that highlighted the nation's religious diversity while unveiling a lineup of clergy members who may serve as advisers and supporters of his administration.
The service in the cavernous limestone cathedral grew surprisingly intimate when a row of interfaith clergy leaders offered prayers for the nation's leaders while standing only a few feet in front of the pew that held President Obama and his wife, Michelle; Vice President Joseph R. Biden Jr. and his wife, Jill; and Secretary of State Hillary Rodham Clinton and her husband, former President Bill Clinton.
"On this day of new beginnings, with hearts lifted high in hope, may we be a people at peace among ourselves and a blessing to other nations," prayed Dr. Ingrid Mattson, president of the Islamic Society of North America.
Standing beside Dr. Mattson, who wore a bright blue head scarf, were two black ministers, two rabbis, an evangelical Christian, an Episcopalian and a Hindu.
Previous national prayer services have featured Muslims and Jews, but the inclusion of a Hindu and a strong representation of women and African-Americans underscored the emphasis on diversity.
The Roman Catholic archbishop of Washington, Donald W. Wuerl; the presiding bishop of the Episcopal Church, Katharine Jefferts Schori; and the primate of the Greek Orthodox Church in America, Archbishop Demetrios, also offered prayers at other moments in the service.
"It was a conscientious effort to have a broad tapestry representing the faces of American religion," said Rabbi David N. Saperstein, director and counsel of the Religious Action Center of Reform Judaism, in Washington.
The participants, prayers and even the hymns were chosen by a committee of Mr. Obama's advisers on religious issues. Altogether, there were three rabbis because the committee wanted to have representatives from the Reform, the Conservative and the Orthodox branches of Judaism (the Orthodox branch usually prohibits participation in a prayer service in a Christian sanctuary).
The Rev. Jim Wallis, a liberal evangelical who is president of Sojourners, a magazine and grass-roots organization based in Washington, said that he and other religious leaders were preparing for a dual role: to challenge the president on policies, and "to clear the way" so people will be prepared to accept the changes he institutes.
"I think Barack Obama understands that big changes won't happen unless there are social movements pushing from the outside," said Mr. Wallis, who has known Mr. Obama for 10 years. "Our job is to change the wind."
The service featured a gospel choir of black children in crisp white shirts and black pants and dresses, many of whom broke into smiles as they filed in and glimpsed the new president. They sang "He's Got the Whole World in His Hands." The president sang along, and the first lady clapped.
For the first time, the main sermon was delivered by a woman, the Rev. Sharon E. Watkins, general minister and president of the Christian Church (Disciples of Christ). She related an oft-told Cherokee tale about a grandfather who explains to his grandson that within every person are two wolves fighting — one the wolf of anger, resentment and fear, the other of compassion, hope and love. The grandson asks which wolf wins, and the grandfather answers, "The one you feed."
Ms. Watkins flattered the president, saying: "It is right that college classes on political oratory already study your words." But then she challenged him, saying, "You, as our president, will set the tone for us. You will help us as a nation choose again and again which wolf to feed."