Our president spoke Sunday night at South Africa's University of Cape Town in the same room where Robert Kennedy spoke in 1966.
Just as Bobby Kennedy did 47 years before, Barack Obama spoke words of encouragement meant not only for Africa, but also for America.
Neither man promised miracles from government.
Rather they beseeched a sense of purpose from each individual in earshot -- each person making up our city, state, country, globe.
Times were different for Bobby Kennedy and Barack Obama -- and Nelson Mandela, whom they both praised. But in many ways, times now are also the same.
Here are the words young Kennedy shared nearly five decades ago in what many have said was his finest speech that aimed at a head-on attack on African apartheid.
"Each time a man stands up for an ideal, or acts to improve the lot of others, or strikes out against injustice, he sends forth a tiny ripple of hope. And crossing each other from a million different centers of energy and daring, those ripples build a current which can sweep down the mightiest walls of oppression and resistance."
Recalling those words Sunday for his own Cape Town audience, President Obama noted that on the very day Kennedy spoke them, the American civil rights leader James Meredith was shot in Mississippi where he was marching to inspire blacks to register to vote.
"Those were difficult, troubled, trying times," Obama said." It would have seemed inconceivable to people at that time -- that less than 50 years later, an African-American president might address an integrated audience, at South Africa's oldest university, and that this same university would have conferred an honorary degree to a President, Nelson Mandela."
Yes, much has changed. But much still should change.
When Obama comes home to America this week, there will still be plenty of room for ripples of hope among the 314 million strong of us here in the United States -- hope that we might find more understanding and tolerance and less hate.
When Obama arrives home, he'll be coming to a House of Representatives that is still stalling immigration reform, to a country where racial fears and divisions continue to play out in the murder trial of George Zimmerman, who is charged with following and shooting an unarmed 17-year-old Trayvon Martin in Florida.
Chattanooga, too, still has problems with race and class. Two former police officers want their jobs back despite the fact that they brutally beat a black disorderly suspect who was not resisting arrest as he was struck by police batons more than 40 times for at least seven agonizing minutes. A Salvation Army halfway house security video captured the scene.
It's so easy for all of us to say government should do this and government should do that, or to call for a new law each time something falls into the gray area of individual judgment.
Nearly five decades ago, when a great American leader called for ripples of hope, and a great African leader took a stand against apartheid even from his tiny cell, what they were saying is that "your voice matters," Obama told Cape Town students.
"That's the power that comes from acting on our ideals," Obama said. And he quickly added that it wasn't just the "giants of history" or governments that brought about change. It is the individual choices of all of us that either divide us -- black from white, Christian from Muslim, tribe from tribe -- or unite us.
"Mandela once wrote, 'No one is born hating another person because of the color of his skin, or his background, or his religion. People must learn to hate, and if they can learn to hate, they can be taught to love, for love comes more naturally to the human heart than its opposite.'" Obama said Sunday.
What a ripple of hope.
Now it's up to us -- mankind.