President Barack Obama stumbled over the word "states" during his swearing-in ceremony on Monday in front of thousands gathered to watch.

Chief Justice John Roberts told President Obama to repeat "the office of president of the United States" but the commander in chief seemed flustered for a moment as he repeated the words. Watch the video below.

In 2009, it was Chief Justice Roberts who made a mistake with the words at Obama's official swearing in. As a result of the fluke, Roberts and Obama repeated the presidential oath in a private ceremony to ensure there were no constitutional issues.

Obama was officially sworn in for a second term on Sunday, in accordance with the Constitution, which requires the presidential term to begin on Jan. 20. Monday's swearing-in was a symbolic ceremony held for the public. Inauguration Day 2013 also had a rare coincidence with Martin Luther King Jr. Day, the second time in history that the two fell on the same day. The first time was in 1997 when former President Bill Clinton was sworn into office for his second term.

The official theme for the 2013 inauguration is "Faith in America's Future," marking the 150th anniversary of the Emancipation Proclamation and the placement of the Statue of Freedom on top of the Capital Dome in 1863.

Beyonce sang the national anthem on Monday. For President Obama's first dance at the inaugural ball in 2009, the "Run the World" singer serenaded the president and First Lady Michelle Obama with "At Last" by Etta James.

On Sunday evening, rapper Lupe Fiasco was asked to get off the stage at a pre-inauguration concert in Washington for performing an antiwar song. He also rapped a refrain that included the lyrics "[Rush] Limbaugh is a racist, Glenn Beck is a racist."

He went on to rap "Gaza Strip was getting bombed, Obama didn't say...That's why I ain't vote for him, next one either."

On Tuesday, President Obama, Vice President Joe Biden - who was also officially had his swearing-in ceremony on Sunday - and their spouses will attend a prayer service at Washington National Cathedral beginning at 10:30 a.m. EST.