Thousands of people gathered at churches across South Africa Sunday for a national day of prayer and reflection in honor of Nelson Mandela, remembering him as the father of a new South Africa.
South African President Jacob Zuma, at a church service in Johannesburg, thanked God for giving Mr. Mandela to South Africa.
His ex-wife, Winnie Mandikizela-Mandela, joined one of his grandsons, Mandla Mandela, and other members of the family for Sunday's service.
World leaders, including U.S. President Barack Obama and U.N. Secretary-General Ban Ki-moon, are traveling to Johannesburg to attend the official memorial service for Mr. Mandela on Tuesday.
The service will be held at Johannesburg's Soccer City stadium - the site of the 2010 World Cup final. Memorial services will also be held in all provinces and regions.
The White House announced that Mr. Obama and first lady Michelle Obama will depart from Andrews Air Force Base near Washington for South Africa on Monday morning.
Former U.S. presidents Bill Clinton and George W. Bush will also attend.
Mandla Mandela thanked mourners during a special service held Sunday by veterans of the African National Congress' guerrilla wing.
"Today you remind us, the Mandela family, of my grandfather's commitment for the liberation of our people. His commitment to the struggle for liberation was indeed cemented in the young men and women that took up arms to liberate our country."
Mr. Mandela's remains will lie in state at the Union Buildings in Pretoria - the official seat of the South African government - on Wednesday, Thursday and Friday.
Officials said Saturday that Mr. Mandela's funeral cortege will travel through the streets of Pretoria, and they encouraged people to line the route.
Mourners have been flocking to sites around South Africa to pay homage to their beloved freedom fighter.
Organizers say they expect about 9,000 people to attend a public state funeral on December 15, in Mr. Mandela's ancestral village of Qunu.
On Saturday, a large crowded gathered in Soweto township where people sang, danced and held up pictures of Mr. Mandela. He lived in the township when he was a young lawyer.