Civil rights leaders, congressional Democrats and labor leaders spoke to the crowd Saturday on the steps of the Lincoln Memorial on the National Mall, where King, on Aug. 28, 1963, delivered what stands as one of the most iconic speeches in American history, capping the historic civil rights March on Washington.
"Those days, for the most part, are gone, but we have another fight," Rep. John Lewis, D-Ga., told the crowd Saturday.
Lewis was a leading figure in the civil rights movement King led, and is the last surviving speaker from the 1963 march.
"There are forces who want to take us back," he said. "But we can't go back."
He joined other speakers Saturday in urging Americans to "make some noise" and advocate for changes in the law following the U.S. Supreme Court decision this year striking down a key provision of the Voting Rights Act, The Hill reported.
"I am not going to stand by and let the Supreme Court take the right to vote away from us," Lewis said.
Speakers also referred to the killing of Trayvon Martin in Florida or advocated for raising the minimum wage, The Hill said.
While none of the homages delivered Saturday were meant to touch the lofty rhetorical standard of King, the remembrances from those who were there -- and the sentiments expressed by those who have been born since -- showed faith his legacy will live on.
"We weren't alive 50 years ago when it happened," Brianna Patterson, 20, told The Washington Post. "Fifty years from now, we can look back and tell our children we were at the 50th anniversary March on Washington. ... We are keeping the dream alive."
The crowd, which stretched back past the Washington Monument's reflecting pool Saturday afternoon, included people who had been waiting since the wee hours of the morning. Organizers told The Hill they expected more than 100,000 people to attend.
Patricia Bent and her friend Sonya Ranson, both of Charlotte, N.C., arrived at the mall at 4:45 a.m. to claim seats alongside the reflecting pool. They were among a few hundred people who arrived overnight.
Bent said she felt obligated to participate.
"We can't take steps back," Bent said. "People fought too long for voting rights. People died. We can't sit back and let their work have no meaning."
And while the focus of the 1963 March on Washington, the actual anniversary of which is Wednesday, was specifically that of civil rights for blacks, the event 50 years later was expanded to include efforts by myriad minority groups seeking what King so passionately expressed, to be judged "not by the color of our skin but by the content of our character."
Eric Holder -- the first African-American U.S. Attorney General -- spoke at Saturday's rally and called for civil rights for all Americans.
"As we gather today, 50 years later, their march -- now our march -- goes on," he said. "And our focus has broadened to include the cause of women, of Latinos, of Asian Americans, of lesbians, of gays, of people with disabilities, and of countless others across this country who still yearn for equality, opportunity, and fair treatment."
The list of speakers was included the Rev. Al Sharpton, president of the National Action Network that organized the event, along with NAACP President Ben Jealous and Democratic lawmakers including House Minority Leader Nancy Pelosi of California and House Minority Whip Steny Hoyer of Maryland.
"When women succeed, America succeeds," Pelosi said. "When people of color succeed, America succeeds."