With Biblical references and the cadences of a preacher, Obama used the refrain, quote, “because they marched,” as he recited the achievements of the Civil Rights movement.

“Because they marched, city councils changed and state legislatures changed and Congress changed and, yes, eventually the White House changed,” Obama said. But he said income inequality, troubled inner cities and stagnant wages amid growing corporate profits show that challenges remain.

“We rightly and best remember Dr. King’s soaring oratory that day, how he gave mighty voice to the quiet hopes of millions, how he offered a salvation path for oppressed and oppressors alike. His words belong to the ages, possessing a power and prophecy unmatched in our time,” the president said.

Former presidents Bill Clinton and Jimmy Carter also spoke, as well as civil rights leader Rep. John Lewis (D-Ga.) and members of King’s family.

Lewis also spoke at the March On Washington on this date in 1963.

“We must never, ever give up,” Lewis said. “We must never, ever give in. We must keep the faith and keep our eyes on the prize.”

Edith Cannon, who used to help organize sit-ins as a college student in Jackson, Miss., told CBS 2’s Danielle Notthingham about the time she met the civil rights icon: “Martin Luther King came once for a rally, and I had my arm in his, and I thought that was so special.”

The final refrain of Martin Luther King Jr.’s most famous speech echoed around the world as bells from churches, schools and historical monuments “let freedom ring” in celebration of a powerful moment in civil rights history.

“My generation takes things a little too much for granted, and if we were to just be aware and really realize how things were back then, we would understand that a lot of things have changed for the better,” he said.

Another student, Tiffany, said she is well aware of how much different her life in school is, compared to back in Dr. King’s day.

“Go around and talk to white people and not be judged; be in the same classrooms as white people – that wasn’t happening 50 years ago,” she said. “So to see it manifest today is just amazing.”

In Clinton Hill, Brooklyn, people filled the pews at the Brown Memorial Baptist Church to hear a message of hope reminiscent of Dr. King’s, CBS 2’s Tracee Carrasco reported.

“I remember that day,” Dr. Ron Daniels, 71, said at the church. “I remember that speech. It was an inspiration.”

He said that day defined his life.

“It let me know as a young man that we were doing something worth fighting for,” he said.

And as CBS 2’s Amy Dardashtian reported, journalist Les Payne of Harlem said dreams have come true since King’s speech.

“Now you have a president — black, African-American — who stands with real power,” he said.

It was a possibility Payne never imagined when he traveled to Washington for the historic speech. Payne was 22 at the time.

“I didn’t go down to hear the great speech by Dr. Martin Luther King,” he said. “Believe me, I was a young guy going down looking at the girls in the area.”

But then, King spoke about the South.

“He said the red hills of Georgia, and that struck me,” he said.

Payne grew up in Alabama, amid rampant segregation.

“When he talked about the brutality that was going on in Mississippi, and in Georgia, and in Alabama — and he talked about the sons and daughters of ex-slaves,” he said.

The speech suddenly became real.

“My grandmother’s mother was a slave, and so I knew about this was very, very — this was not abstract for me,” he said. “This was stuff that hit me as close to the bone as you can get.”

The speech lived on. When Payne became a father, he taught his children King’s words.

“I’m sure they were rolling their eyes — here comes dad again with the album,” he said.

Now a Pulitzer Prize-winning journalist, Payne holds his button from that day, and marvels at how far society has come. But also wonders where we’re headed.

“Black unemployment is twice that of whites, and then you say, the question is, well, can you do something about this?” he said.

Payne said Dr. King diagnosed a problem “still alive today, working for a cure.”

And in Connecticut, Gov. Dannel P. Malloy asked residents and organizations to ring bells to mark the 50th anniversary. The official bell-ringing was held at 3 p.m. in Hartford, while the governor joined the bell-ringing at the Mt. Olive AME Zion Church in Waterbury. He was also scheduled to give remarks at “The Dream Continues Ceremony” in Manchester.

Gov. Dannel Malloy at Mt Olive Church in Waterbury for 50th anniversary of MLK’s “I Have A Dream” speech. (credit: Twitter/Gov. Malloy’s Office)

Malloy said the civil rights leader’s “message of freedom, equality and liberty resonates as strongly today as it did 50 years ago.”

King’s family invited every state to participate in the day of remembrance by ringing bells in unison at churches, schools and other venues where there are bells.

Despite the progress in the Civil Rights movement over the past five decades, Malloy questioned why some southern states have recently decided to impose new laws encroaching on voters’ rights.

“We’re seeing states pass requirements for voter ID that are onerous particularly to urban dwellers, to senior citizens, to people who don’t drive cars and that sort of thing — rules that we never had before,” Malloy told WCBS 880 Connecticut Bureau Chief Fran Schneidau.

Malloy said the 50th anniversary offers all residents an opportunity to think about areas where equality remains lacking.

“I think the dream of peace and freedom and liberty intertwined with civil rights or rights across the board with respect to gender or choice – these are all things that we should all set aside to think about,” he told Schneidau. “I think education, particularly in our urban areas, is the civil rights issue of our time. How do we get it right. We’ve got to break away from this idea that we distribute opportunity. What we have to do is distribute success in our schools.”

President Obama also said the anniversary is a good time to reflect on how far the country has come and still has to go.