That was in 1976. It was a measure of the political consistency of Treurnicht, a minister of the Dutch Reformed Church, that 17 years later he went to his death believing there was no conflict between apartheid and the teachings of Christ.
Chris Hani, who was buried last week, was the leading Communist in the African National Congress (ANC) and, though having contemplated the priesthood in his youth, he fought against everything that Treurnicht held dear.
It was fitting that in death, as in life, the two should have remained planets apart. All that the funerals of Treurnicht and Hani had in common was that in each case there was a grave, a coffin and a body.
Hani's funeral service was held at a soccer stadium crammed with 100,000 mourners. Although 'mourners' was perhaps not quite the word to convey a mood that combined grief, jubilation and anger, tears, dancing and burning buses.
The ceremony yesterday, conducted under the African midday sun, had a distinctly northern European, Calvinist flavour to it. Quite properly, politics were off the agenda.
About 800 people stood, heads bowed, for an hour inside a gaunt, red-brick church in central Pretoria listening to Old Testament exhortations by a minister, Kobus Potgieter, who reminded the congregation of the story of Abraham being prepared to kill Isaac. This perhaps gave food for thought to the one black man inside the church, Brigadier Oupa Gqozo, leader of the Ciskei 'homeland'. The brigadier, known in ANC circles as 'the Butcher of Bisho' after the massacre he ordered in September, was a welcome guest, having embraced a system that ensured blacks would live, work, vote and marry in a different world from whites.
About 100 yards away, in Church Square, the service was carried on a loudspeaker system to another 800 or so mourners standing beneath a statue of Paul Kruger, the Boer leader, who fled South Africa half-way through the Boer War and died in exile, quite persuaded that the earth was flat.
Two thousand people marched, in dignified silence, the half mile to the cemetery, where Treurnicht was laid to rest alongside the former prime minister Hendrik Verwoerd, the apartheid theologian from whose orthodoxies the Conservative Party leader refused to deviate.
The style of dress of the marchers was set by a number of five and six- year-old boys, who wore dark suits and ties. No dancing, no singing, no T-shirts, no banners. Political insignia were worn, if at all, on the lapels - the swastika-like triple seven, for example, of Eugene Terreblanche's AWB. The one concession to colour was Treurnicht's coffin, wrapped in a South African flag; Hani's had been draped in an ANC one.
At the graveside, where white schoolboys in blazers provided a guard of honour, a solitary trumpet played - first a dirge, then the white South African national anthem, 'Die Stem', the words of which the mourners defiantly sang.
All over Pretoria, flags flew at half-mast, over the Supreme Court building, over South African Police headquarters. Meanwhile, a police spokesman announced that a court application had been lodged for the Conservative Party official, Clive Derby-Lewis, an old and close associate of Treurnicht's, to be held for an extra 10 days in connection with the assassination of Hani, the original 10-day limit permitted under the Internal Security Act having expired.