John Lewis told BU’s Class of 2018 Sunday to enjoy their big day—then get to work.

“Take a long, deep breath, take it all in—and roll up your sleeves, because the world is waiting for you, waiting for talented men and women to lead it to a better place,” the civil rights leader said in his Commencement speech.

“My philosophy is simple. When you see something that is not fair, not right, not just, then you have a moral obligation to say something, to do something, stand up, speak out,” said Lewis (Hon.’18) (D-Ga.), the US representative from Georgia’s fifth congressional district since 1987, to the 7,072 graduates and 20,000 guests at Nickerson Field for the University’s 145th All-University Commencement. His impassioned oratory drew repeated standing ovations.

The ceremony began 20 minutes ahead of schedule, because the weather forecast called for thunderstorms, which never materialized, with the sun coming out and remaining mostly out until the end.

Lewis, one of the 13 original Freedom Riders, was beaten and jailed repeatedly during the Civil Rights Movement. He helped organize the 1963 March on Washington, where his friend and mentor, Rev. Martin Luther King, Jr. (GRS’55, Hon.’59), delivered his famous “I Have a Dream” speech. He spoke of writing a letter to King when he was 17, and King’s eventual invitation to meet with him in Montgomery, Ala., an invitation that led to a long friendship and Lewis’ prominent role in the Civil Rights Movement. He told the crowd that King spoke often about BU and the faculty and scholars he learned from here.

The longtime Georgia congressman told of growing up in the Jim Crow South, of signs everywhere marking separate facilities for “whites” and “colored.” When he asked his parents and grandparents about them, though, they told him that it was just the way life was and urged him not to get in trouble.

“I got in trouble! I got in trouble!” said Lewis, recounting dozens of arrests for protesting over the years. “I gave a little blood, but some people gave their lives.”

Change, he told the Class of 2018, is possible when people act courageously. Today, the only places you see those “whites” and “colored” signs are in a book, a museum, or a video, Lewis said, but much work remains to be done. While he didn’t mention the current occupant of the White House by name, he made a point of noting that both our democratic ideals and our planet are in trouble, adding: “We need young men and women, smart graduates of Boston University, to go out there and get into trouble.

“I urge you as you leave here, to participate in the democratic process, to get out there and vote like you never voted before,” he said to cheers from the crowd. “Be optimistic, don’t get lost in a sea of despair, but be bold, be courageous, and all will work out.”

President Robert A. Brown presented Lewis with a Doctor of Laws, saying, “You stand before us as an icon of the Civil Rights Movement, but also as a reminder that the fight for justice is never easy and it is never over. In your courage, we find the inspiration to carry on that fight. And we are better for it, both as a society and as individuals.”