Barack Obama, John Lewis discuss Martin Luther King Jr.'s legacy in new video

Former President Barack Obama and Congressman John Lewis appeared in a video honoring Dr. Martin Luther King Jr. on Wednesday as the nation commemorates the 50th anniversary of the civil rights leader's assassination.

The video, released by the Obama Foundation, features the 44th U.S. president and Democratic representative from Georgia sitting down with young leaders, discussing King's legacy and its modern imprint in an increasingly polarized nation.

Lewis, who marched with King and other civil rights activists in the 1960's as a teenager, described being with Robert F. Kennedy's campaign in Indiana when he learned of King's death. Kennedy went on to deliver a powerful speech that night from the bed of a truck, echoing the slain reverend's message of love, compassion and equality.

"It was a very sad and dark time for me. He was my leader, he was my inspiration," Lewis said, speaking to Ron Brown College Preparatory High School students in Washington, D.C. "But when he was assassinated, I said 'you cannot get down. You have to pick up and keep going."

Click to watch the full video below:

Lewis — who Obama notes as the only living speaker from the March on Washington — went on to discuss his remarks given on August 28, 1963, saying some thought his speech was "too extreme," but that he knew speaking out on voting rights in the South was an important topic.

"If you are speaking on behalf of social justice, by definition there's going to be some controversy," Obama added. "Dr. King was controversial, but he studied and thought and crafted what he had to say. And he knew when he spoke he was expressing a truth as well as he could know it."

RELATED: Remembering Martin Luther King Jr.

Lewis has served in Congress since 1986 and has recently been a vocal opponent of President Trump's platform and agenda. In January, he called Trump "a racist" during a CNN segment, adding that he would not attend the 45th commander in chief's State of the Union address later that month.

"Part of what you always want to communicate to young people is that being on the right side of history isn’t always popular, and it isn’t always easy," Obama says in the video. "And you don’t know when things are going to break your way, you don’t know whether your labors will deliver."

Lewis referred back to Dr. King's legacy in closing the online segment, saying, "When you see something that is not right, not fair, not just, you have a moral obligation to do something."

RELATED: A look back at the March on Washington in 1963