In his speech at a historic memorial service for Nelson Mandela, President Obama called the first black president of South Africa “a giant of history” and urged people around the world to make “his life’s work your own.”

“Over 30 years ago, while still a student, I learned of Nelson Mandela and the struggles taking place in this beautiful land, and it stirred something in me,”  Obama said at a ceremony attended by dozens of world leaders and thousands of South Africans in a stadium in Johannesburg. “It woke me up to my responsibilities to others and to myself, and it set me on an improbable journey that finds me here today.  And while I will always fall short of Madiba’s example, he makes me want to be a better man. He speaks to what’s best inside us.”

In the speech, Obama cast Mandela as “the last great liberator of the 20th century,” likening his achievements to Gandhi, Martin Luther King, Jr. and Abraham Lincoln. Obama argued Mandela was more than just a “bust made of marble,” but both a “leader of a movement” and a “skillful politician.”

“In the arc of his life, we see a man who earned his place in history through struggle and shrewdness; persistence and faith,” the president said.

Obama concluded his 19-minute address by talking about how Mandela’s example should influence people around the globe.

“Madiba’s passing is rightly a time of mourning, and a time to celebrate a heroic life.  But I believe it should also prompt in each of us a time for self-reflection.  With honesty, regardless of our station or our circumstance, we must ask:  How well have I applied his lessons in my own life?  It’s a question I ask myself, as a man and as a president,” Obama said.

Obama’s answer was that honoring the legacy of Mandela should include efforts “to promote equality and justice, “to uphold freedom and human rights, “and “to end conflict and sectarian war.”

“There are too many people 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. “There are too many leaders who claim solidarity with Madiba’s struggle for freedom, but do not tolerate dissent from their own people.  And there are too many of us on the sidelines, comfortable in complacency or cynicism when our voices must be heard.”