President Obama celebrated Nelson Mandela as the “last great liberator of the 20th century” Tuesday before a cheering crowd and host of world leaders who gathered in a soccer stadium in Soweto to pay tribute to the former freedom fighter and first black president of South Africa.

Describing the “great soul” of a man who conquered apartheid and became a “giant of history” by peacefully ushering in the country’s first era of biracial government, Obama said, “It took a man like Madiba to free not just the prisoner, but the jailor as well.”

Amid an unrivalled collection of the world’s most powerful leaders, Obama shook hands with Cuban president Raúl Castro and kissed Dilma Rousseff, the Brazilian president, before taking to the stage to give one of the day’s most rapturously received eulogies, five days after the death of Mandela, who is known affectionately as Madiba.

Obama said it was not enough to merely celebrate the life of a great man, he called on those leaders sitting alongside him and millions more people watching on television to take inspiration from Mandela’s achievements. "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,” he said. “When the night grows dark, when injustice weighs heavy on our hearts, or our best laid plans seem beyond our reach, think of Madiba.”

The dancing crowd, diminished by torrential rain, raised their arms aloft when Obama quoted from Mandela’s most famous speech, which was given in the dock of a South African courtroom before he was condemned to spend almost three decades in a jail cell. “‘I have fought against white domination and I have fought against black domination,’ he said at his 1964 trial. ‘I’ve cherished the ideal of a democratic and free society in which all persons live together in harmony and with equal opportunities. It is an ideal which I hope to live for and to achieve. But if needs be, it is an ideal for which I am prepared to die.’”

Obama reflected on his personal relationship to the legacy of Mandela. “Michelle and I are beneficiaries of that struggle,” he said. But he also delighted the crowd with his close knowledge of the anti-apartheid movement. He paid tribute to lesser-known leaders of the struggle, using local phrases and words.

“Mandela understood the ties that bind the human spirit,” Obama said. “There is a word in South Africa—ubuntu—that describes his greatest gift: his recognition that we are all bound together in ways that can be invisible to the eye; that there is a oneness to humanity; that we achieve ourselves by sharing ourselves with others, and caring for those around us.”

Obama’s words were welcomed by the crowd who also cheered Ban ki-Moon, the U.N. Secretary General, Castro, Robert Mugabe and members of Mandela’s family. Not everyone was well-received, however, organizers appealed to the crowd to show respect when every glimpse of the current South African president Jacob Zuma was greeted by a chorus of boos, President George W. Bush was also jeered by the half-full stadium.

Click here to read the Obama’s full eulogy.