IT WAS AN extraordinary scene, even for South Africa: an angry black crowd sensing betrayal, a car turned upside down and set afire, and Bishop Desmond M. Tutu, in purple clerical robes, moving through the people to wave them off a gasoline- doused man -- a black man -- who, were it not for the bishop's intervention, would surely now be dead.

The crowd in Duduza accused its victim of being a police informant. For this he would be dealt with as have been the many township councillors, deputy mayors and the like: hacked to death or set afire -- deeds seen as fit punishment for turning against one's own.

In the televised film you could see Bishop Tutu and Bishop Simeon Nkoane moving in the crowd, gesturing urgently without laying on a hand. "This undermines the struggle," Bishop Tutu cried, acting out his philosophy of nonviolent resistance at extraordinary personal risk.

This is the same Bishop Tutu who, three years ago, confronted a large, white policeman beating an elderly black man with a stick and held a cross aloft until the beating stopped. In late 1981, a black crowd at a funeral attacked another suspected police informant, and Bishop Tutu flung himself across the victim, persuaded the attackers to back off and then gave a service wearing clerical robes soaked with the man's blood.

More than 400 blacks have been killed in political violence in South Africa in the past 10 months. Just days ago, it was the police who committed the violence, in Kwa Zema. Witnesses said the police fired tear gas and rubber bullets indiscriminately into a movie house, where frightened mourners had fled from police after an all-night service for still other black youths killed in a hand-grenade explosion weeks before. Seven died.

Violence against blacks -- whoever commits it -- is the infection of apartheid. "Many in the black community, incensed at the injustice of apartheid, believe that anyone who collaborates in . . . the apartheid system is a co-oppressor," Bishop Tutu said after the Duduza attack. "And you will recall that collaborators were dealt with very, very harshly, with summary justice, during World War II in the resistance movement. . . . This is not to condone what is done to them, but it is to say that it is a phenomenon that is universal. And our own effort, as the church, is to try and say any form of violence is unacceptable and will not in the end solve the problems of our country amicably."

What will "solve the problems of our country amicably" is, of course, the example of Bishop Tutu's nobility of spirit and a decision by the current white rulers to reach out to people such as him who have the capacity to save South Africa.