The dedication was originally scheduled for late August but was postponed after Hurricane Irene swept through the Washington region, dumping rain on the nation's capital and disrupting travel plans for many of those who planned to attend the event.
On Sunday, Obama will speak in front of a 30-foot sculpture of King, arms crossed, looking out into the horizon. The civil rights leader appears to emerge from a stone extracted from a mountain. The design was inspired by a line from the famous 1963 "Dream" speech delivered during the March on Washington in 1963: "Out of the mountain of despair, a stone of hope."
Obama once contemplated what it would be like to take his two daughters to see a national monument to the slain civil rights leader.
"I know that one of my daughters will ask, perhaps my youngest, will ask, "Daddy, why is this monument here? What did this man do?" Obama, then a senator representing Illinois, said during a 2006 groundbreaking ceremony for the memorial to the civil rights pioneer.
Five years have passed since Obama reflected on those questions. The young senator is now president, and the King memorial is complete, having opened to the public in August. And Obama will get his chance to take daughters Malia and Sasha to the monument Sunday for the dedication ceremony, during which the country's first black president will be a featured speaker.
Situated between the Lincoln and Jefferson memorials, King's is the first monument on the National Mall honoring a black leader.
Obama was just 6 years old when King was assassinated in Memphis, Tenn. But he has often talked about the influence King's life, particularly his commitment to public service, has had on him.
In a 2009 newspaper editorial written just days before his inauguration, Obama wrote that King "lived his life as a servant to others," and urged Americans to follow his example and find ways to enrich people's lives in their communities and across the country.
Valerie Jarrett, a White House senior adviser and longtime friend of the president, said she expects the president's remarks "to come straight from the heart."
King's "willingness to sacrifice himself for our country, to fight for a dream he believed in, like justice and equality, really gave a foundation for President Obama becoming the president," Jarrett said.
Obama is also looking forward to the opportunity to speak as a parent and to remind his daughters and other young people about the work that went into securing the liberties they may now take for granted, Jarrett said.
When Obama imagined years ago taking his daughters to see the King monument, he couldn't have known he would do so as president. But he said when the monument was complete, he would tell his daughters "that this man gave his life serving others. I will tell them that this man tried to love somebody. I will tell them that because he did these things, they live today with the freedom God intended, their citizenship unquestioned, their dreams unbounded."