At a memorial service in Johannesburg, Obama compared the former South African President to Mahatma Gandhi, Martin Luther King Jr. and Abraham Lincoln. He said Mandela had earned his place in history through struggle, shrewdness, persistence and faith.
"For nothing he achieved was inevitable," Obama said. "In the arc of his life, we see a man who earned his place in history through struggle and shrewdness, persistence and faith. He tells us what's possible not just in the pages of dusty history books, but in our own lives as well."
In a rain-soaked stadium where world leaders gathered to honor the anti-apartheid leader, Obama traced the influence that Mandela's story has had on his own life, disclosing that he asks himself how well he's applied Mandela's lessons to himself as a man and as president.
He said in the U.S., South Africa and around the world, people must not allow progress that's been made to cloud the fact that more work must be done.
"We, too, must act on behalf of justice. We, too, must act on behalf of peace. There are too many of us who happily embrace Madiba's legacy of racial reconciliation, but passionately resist even modest reforms that would challenge chronic poverty and growing inequality," Obama said, referring to Mandela by his traditional clan name.
Joining Obama on the 16-hour trip from Washington for the ceremony were first lady Michelle Obama, former President George W. Bush and his wife, Laura, and former Secretary of State Hillary Rodham Clinton. Former Presidents Bill Clinton and Jimmy Carter also attended the memorial service.