(CNN) -- Martin Luther King Jr. was remembered Saturday as an irrepressible civil rights leader who many times triumphed over a "mountain of despair."
"Everywhere he went, the mountain of despair was thrust upon him by the evils" of the world, said former United Nations ambassador Andrew Young during a national prayer service at the Basilica of the National Shrine of the Immaculate Conception in Washington.
"You and I must become stones of hopes in the midst" of the mountains of despair, Young told the congregation. Young was a top aide to King during the civil rights movement.
The Rev. Joseph Lowery, another leader during the civil rights movement and former president of the Southern Christian Leadership Conference, cited how Saturday's service also held an indomitable spirit.
"After all the things black folk been through, ain't no little hurricane gonna stop us," Lowery said.
Then referring to how a recent quake damaged some Washington landmarks and not others, Lowery added: "Earthquake may have messed with a chip of the (National) Cathedral, but it knows better than to mess with the black monument."
Saturday's prayer service was originally to be part of a series of events this weekend that were supposed to culminate Sunday with the dedication of the Martin Luther King Jr. National Memorial in Washington.
But the dedication had to be postponed because of Hurricane Irene's expected advance on the U.S. East Coast.
Harry Johnson Sr., head of the Dr. Martin Luther King Jr. National Memorial Foundation, said the dedication of the memorial will be moved to a still undetermined date in September or October.
On Thursday, Johnson told reporters that foundation officials postponed the Sunday event out of concern for visitors' safety, after consulting with officials and forecasters tracking the storm.
"The obvious reason why we're making this announcement is to allow those folks who have not yet traveled here the opportunity not to come in harm's way," Johnson said. "We're also offering up the opportunity for those who are here, that if they want to try to leave, they can leave before the weather gets bad on Saturday."
President Barack Obama had been scheduled to dedicate the site, near Washington's Tidal Basin between the Lincoln Memorial and the Jefferson Memorial, in a ceremony starting at 11 a.m. Sunday.
Obama has declared emergencies in eight states ahead of the hurricane.
The site of the 30-foot granite sculpture of the late civil rights leader opened to the public Monday. Groundbreaking took place in November 2006, and Sunday's planned dedication was timed with the 48th anniversary of the March on Washington, where King delivered his historic "I Have a Dream" speech.
CNN's Andy Rose, Jason Hanna and Paul Courson contributed to this report.