Many South Africans will revere Mr Mandela, who during his life became a global symbol of peace and reconciliation, even more now that he has died, since ancestors are widely believed to have a guiding, protective role over the living.
Around 46% of the population practises traditional African religions, according to a 2010 survey by the Pew Forum on Religion & Public Life, a Washington-based research centre.
Mr Mandela, of the abaThembu people and South Africa's first black president, died a week ago at the age of 95. Thousands of people have filed passed his body as it lies in state in Pretoria this week.
He will be buried by his family following their traditional burial rites on Sunday in Qunu, their ancestral home in the rural Eastern Cape province, 450 miles south of Johannesburg.
If the rites are not carried out, the abaThembu believe the dead will come back in spirit to demand they are performed.
"We as Africans have rites of passage, whether it is a birth, marriage or funeral. Mandela will be sent off into the spiritual world so that he is welcomed in the world of ancestors. And also so that he doesn't get angry," said Nokuzola Mndende, a scholar of African religion. A man who for many embodied the Christian values of forgiveness, Mr Mandela was the product of Xhosa traditional upbringing and Methodist schooling.
Mr Mandela spoke approvingly of the Xhosa rituals which his mother, a convert to the Methodist faith, resisted but his father followed. For the abaThembu, the ritual of accompanying Mr Mandela's spirit will include the slaughtering of an ox in the early hours of tomorrow morning before receiving his body, flown in from Pretoria.
In the early hours of Sunday morning, before the funeral officially begins, another ox will be slaughtered as part of the family ritual of saying goodbye.
After that Mr Mandela's body will be handed over to the church and then to President Jacob Zuma for the state funeral.