If Nelson Mandela was a cellist, instead of a freedom fighter, one might say that he played every string of society superbly on his trip here this week.

As the Mandela music resonated from the White House to Capitol Hill to the Washington Convention Center, these were among the sounds I heard:

The Bush String: While rebuffing President Bush's demand that violence end by stating that he could not now completely renounce the use of armed struggle in the fight against apartheid, Mandela still obtained the assurance he sought that U.S. economic sanctions will remain in place.

The Congress String: Charming a crowded House chamber with his candor, the former political prisoner and first African non-head of state to address a joint session of Congress called for added financial assistance in the struggle against "the apartheid crime against humanity."

While some lawmakers said Mandela's stand on violence would keep Congress from sending the African National Congress more than the

$10 million voted earlier this year to build democratic institutions in South Africa, others cited a double standard based on race. "Only in the case of South Africa," said Rep. Howard Wolpe (D-Mich.), "has the doctrine of nonviolence emerged as a central element in our policy. Race gets in the way of our seeing the struggle . . . as the same as our own."

What was striking in the groundswell of congressional support for Mandela -- Senate President pro tempore Robert C. Byrd (D-W.Va.) applauding, the 19 ovations he received from congressional representatives during his speech, the frank awe with which senators attending a private dinner treated him -- all these made me realize that the man may have started an earthquake that has rent the political fabric in such ways that it can never be put together again.

The African-American String: Not since the television experience of "Roots" have I seen blacks come together as powerfully as they did for Nelson and Winnie Mandela. As the Mandelas manifested a heroism that touched each life in an incredible way, many blacks renewed their relationship to Africa.

The visit was transforming in that it brought to many African Americans a quality that had not existed earlier -- a feeling of being bigger and better than before their encounter with the Mandelas.

Now African Americans have the challenge to form a powerful pressure group for international issues, for Mandela helped them understand anew their commonality of interest with Africa. If they really feel and act on the roots he symbolized, they will lobby not only for sanctions but also for financial aid for the African National Congress, and help the larger continent as well. One friend of mine suggested that black entertainers and others should sponsor a national ANC Day, with a goal of raising $20 million. "That," she said, "would be black power."

I expect the Mandela visit to spur the black activism in America that already has begun. This year alone, blacks have protested in Selma, Ala., New York and other cities. Last week, black students came here from around the country to demand that the government put education at the top of its agenda and also be alert in uncovering and damning racism.

If Mandela's humility, eloquence and strength were striking, his morality is a challenge to our own commitment.

"It would have been immoral to keep quiet while a racist tyranny sought to reduce an entire people into a status worse than that of the beasts of the forest," he told the Congress. "It would have been an act of treason against the people and against our conscience to allow fear and the drive towards self-preservation to dominate our behavior, obliging us to absent ourselves from the struggle . . . . "

If black Americans can respond to what Mandela is saying -- that it is immoral and treasonable for them to fail in America given the relative advantages over South Africa -- he will have brought here a terribly important source of strength.

Indeed, the whole visit was a symbiotic process in which Mandela, coming in search of resources and assurances, left strength, hope and challenge.

To the extent that Mandela is playing all the strings of this society, one has reason to hope that even if for a moment one of those strings vibrates and lifts the spirit, morality and cultural values of those who are in jail, on drugs or needlessly dying on the streets for lack of hope, he will have brought a much-needed miracle.