Thousands of people filled West Potomac Park today for the postponed dedication of the Martin Luther King Jr. Memorial, which included speeches by President Barack Obama and King’s relatives.

“I witnessed a baby become a great hero to humanity,” said Christine King Farris, the slain civil rights leader’s older sister.

The sunny Sunday morning ceremony was the culmination of years of work toward building the first monument on the National Mall to represent an African-American and a non-president. Congress passed and President Bill Clinton signed legislation in 1996 to establish the King memorial in Washington, but it took another decade of legislation, designs and fundraising before ground was broken on the project on Nov. 13, 2006.

The memorial was first opened to the public in August, and a huge dedication ceremony was planned for Aug. 28, the anniversary of King’s “I Have A Dream” speech. However, Hurricane Irene’s path up the East Coast forced officials to postpone and scale back the event.

King’s daughter, Bernice King, referenced the liberal “Occupy” movement that has set up camps in Washington, D.C., New York and other cities to protest corporate greed and unrestricted political money.

“We should never adjust to the 1 percent controlling more than 40 percent of the wealth,” she said. “We should never adjust to an unprecedented number of people being unemployed.”

Her brother, Martin Luther King III, followed her lead, saying the time had come to “show the world our greatness, to throw off the shackles of all the conservative policies that exclude masses of people.”

Obama delivered a message of change and hope, bringing to mind his 2008 presidential campaign.

“Let us remember that change has never been quick,” he said. “Change has never been simple or without controversy. … [King] kept on pushing, he kept on speaking, he kept on marching until change finally came.”

He said King would want politicians to “stand in the other person’s shoes, to see through their eyes, to see their pain.”

Rep. Hansen Clarke sat in the audience, nodding as the president spoke. He said he liked the idea of progress and moving forward.

“We need to be working for what’s possible, not be trapped by what’s happened,” the Michigan Democrat said.

D.C. Mayor Vincent Gray brought a different political message to the ceremony, using his moment on stage to support full voting representation in Congress for the District.

King’s dream “remains unfulfilled in the District of Columbia,” he said.