Rep. John Lewis, D-Ga., urged students on Saturday to help recreate a sense of hope that has been lost in America today and to participate in civil disobedience if necessary.

In a commencement speech that focused largely on Lewis' life growing up and his involvement in the civil rights movement in the 1960s, Lewis ended it with an examination of the current state of affairs and a thinly veiled critique of America under President Trump, whom he did not mention by name.

After quoting Dr. Martin Luther King's famous line, "We must learn to live together as brothers or perish together as fools," Lewis warned graduating students at Massachusetts College of Liberal Arts that "there's a mean spirit in America today."

He said that during the early 1960s, under President John F. Kennedy, "there was a greater sense of hope and a greater sense of optimism" compared to today.

"We must rebuild that sense of hope, that sense of optimism and never let anything get you down," he said.

Paralleling what he said earlier about getting into the way of things he saw as unjust during the civil rights era, Lewis encouraged his audience to do the same when they leave college.

"Go out there, get in the way, get in trouble — good trouble, necessary trouble and make some noise," he said to cheers.

"Our country needs you now more than ever before," Lewis said. "When you see something that is not right, not fair, not just, you have a moral obligation, a mandate - to stand up, speak up and speak out."

Watch Lewis' full commencement address below: