President Barack Obama will address his sixth annual National Prayer Breakfast on Thursday, where he is expected to tell an audience of both liberals and conservatives about what motivates him.
The National Prayer Breakfast has been held for 62 years, and last year Obama said it shows faith can bring people together.
"It says something about us that every year, in times of triumph and in tragedy, in calm and in crisis, we come together, not as Democrats or Republicans, but as brothers and sisters, and as children of God," he said.
Gatherings that focus on prayer are an integral part of Washington's political calendar and the president's attendance is often expected.
"People expect to have a president of strong religious faith," said public policy professor Mark Rozell, an expert on religion and the presidency. "And they are comfortable with the president engaging in public displays of religious faith and commitment."
But not everybody agrees.
Barry Lynn is a minister in the United Church of Christ and director of Americans United for Separation of Church and State.
"Technically, it is not a violation of the Constitution for the president of the United States to go to a religious event that is off public property," Lynn said. "This is held in a big hotel. But I am very troubled by the way that politicians in the United States tend to want to use religion for political purposes, giving speeches that quote Jesus, as if Jesus was supposed to be making decisions about how we develop an anti-gun policy or run a budget."
Obama concedes that politicians do not suddenly become more virtuous by attending.
"I do worry sometimes that as soon as we leave the prayer breakfast, everything we have been talking about the whole time at the prayer breakfast seems to be forgotten, on the same day of the prayer breakfast,” he said.
But it does allow the president a rare opportunity to expound on his own faith and how it underlies his policies.