"I can see Madiba smiling when I say 'President Cyril Ramaphosa'."

These were the words from Nelson Mandela's widow Graca Machel who yesterday gave an indication that her late husband would have been happy to see Ramaphosa leading the ANC and government.

She was among the many influential people who gathered in Johannesburg to celebrate Mandela's 100 years during a lecture delivered by former US president Barack Obama.

Machel said such celebrations would have made Madiba happy.

She said Madiba and Obama gave hope and validation to people because they came from humble backgrounds.

Chairman of the Nelson Mandela Foundation, Njabulo Ndebele, said Ramaphosa had so far shown he was serious about getting rid of corruption in government.

He said the lecture was the biggest ever to be hosted by the foundation, and was in line with late Struggle icon Ahmed Kathrada's wish that the lecture be held at a stadium.

Ndebele recalled how Madiba walked out of prison 24 years ago with his fist in the air, holding the late Winnie Madikizela-Mandela's hand.

He said at the time the country was waiting for his leadership, and he never failed.

Ramaphosa said he could hear Madiba whispering in his ear: "I am sending you to serve the nation."

He also said his Thuma Mina slogan was inspired by Madiba.

"Madiba is sending us to root out corruption."