Two challenges face Bishop Desmond Tutu of South Africa: confronting his opponents and educating his followers. The second may be harder.

Mass mobilization for nonviolence among the blacks of South Africa means persuading the powerless that noncooperation and civil disobedience are more effective for reform than fists, guns or bombs.

In his commitment to peaceful change, Tutu has chosen the strategy of nonviolence. He is both a theorist who has written about its effectiveness and a practitioner who has successfully applied it. Last week in Daveytown, South Africa, Tutu negotiated for 20 minutes on a public road with white police officers. He persuaded them to assist rather than thwart mourners as they moved from a funeral to a cemetery.

During the negotiation, the police, backed by armed troops, had martial force. Tutu, steeled by the strength that "God's word burns like a fire in my breast," had moral force. On that particular day, Tutu prevailed. He knew he couldn't bring the police to their knees, so he brought them to their senses, which was harder.

The achievement appears small when compared to the violence in South Africa this summer. More than 50 people have died since a state of emergency was declared nearly four weeks ago in 36 cities and towns. Five hundred people have been killed in the past year.

Tutu himself, in a recent venting of frustration, threatened to leave South Africa if blacks did not stop killing other blacks whom they suspected of collaborating with the government. The Nobel Peace Prize winner said that the reaction to his nonviolence by many young black activists was negative. He repeated their view: "Let him go, then we can get on with the revolution without him restraining us."

This is not new pressure for Tutu. Four years ago he wrote of his exasperation in the slowness of winning political power-sharing for blacks: "More and more blacks are becoming disillusioned as those of us calling for change by peaceful means have our credibility eroded by the action of the authorities, often brutal and excessive action."

The following year, he wrote: "Our people are rapidly despairing of a peaceful resolution in South Africa. Those of us who still speak 'peace' and 'reconciliation' belong to a rapidly diminishing minority."

Tutu's anguish is linked historically to the work of an earlier practitioner of nonviolence in that country, Mohandas K. Gandhi. Twentieth-century pacificism originated in South Africa with Gandhi's organizing Indians in 1906 to resist a number of laws, including one requiring them to be registered with 10 fingerprints. Criminals are fingerprinted, Gandhi argued, not human beings.

The struggle lasted from 1906 to 1914. Several attempts on Gandhi's life were made. He was jailed repeatedly. But when he left South Africa for home in 1914, reforms had been won. During those years, Gandhi adopted "satyagraha," the doctrine of "soul force" that he was to practice for the rest of his life.

Gandhi faced a constant tension in mobilizing followers to nonviolence. His situation in India was similar to Tutu's today: a constituency of large numbers. Some 350 million Indians were ruled by 100,000 Englishmen. In South Africa and its black states, it is 16 million blacks to 4.6 million whites. The other similarity, the confounding one, is the pluralism in the majority that made organizing a torment.

Blacks killing blacks in today's South Africa goes back to Gandhi's pre-independence India when factions of Hindus fought each other. When enough of that blood was spilled, Hindus and Moslems fought. Uniting Indians was as much an ordeal as driving out the British. Gandhi in his autobiography recalled that before "starting civil disobedience on a full scale, it would be necessary to create a band of well-tried, pure-hearted volunteers who thoroughly understood the strict conditions of satyagraha. They could explain these to the people, and by sleepless vigilance keep them on the right track."

It achieved results but not large ones: "While this movement for the preservation of nonviolence was making steady though slow progress on the one hand, (the) government's policy of lawless repression was in the full career on the other."

Gandhi did not yield, nor does it seem likely that Desmond Tutu will either. The South African has said he is ready to be jailed for "preaching the Gospel of the Lord Jesus Christ" and he is ready to die: "The most awful thing that they can do is to kill me, and death is not the worst thing that could happen to a Christian."

Tutu has been drawing on the strengths of the Gandhian tradition. The moral force of nonviolence is the only one that can prevail and last. In South Africa, Tutu is offering the choice.