[W]e felt that without sabotage there would be no way open to the African people to succeed in their struggle against the principle of white supremacy. All lawful modes of expressing opposition to this principle had been closed by legislation, and we were placed in a position in which we had either to accept a permanent state of inferiority, or to defy the Government. We chose to defy the Government. We first broke the law in a way which avoided any recourse to violence; when this form was legislated against, and when the Government resorted to a show of force to crush opposition to its policies, only then did we decide to answer violence with violence.
But the violence which we chose to adopt was not terrorism. We who formed Umkhonto were all members of the African National Congress, and had behind us the ANC tradition of nonviolence and negotiation as a means of solving political disputes. We believed that South Africa belonged to all the people who lived in it, and not to one group, be it black or white. We did not want an inter-racial war, and tried to avoid it to the last minute.Throughout the 1970s and 1980s, as international opposition to apartheid grew and multinational corporations (banks, especially) began to find the pressure from shareholders as well as consumers increasingly difficult to stave off, Mandela became such a focus of international concern that the South African apartheid regime that in the mid-1980s President Botha tried bargaining with Mandela for his release. Heroically Mandela replied: "What freedom am I being offered while the organisation of the people remains banned? Only free men can negotiate. A prisoner cannot enter into contracts." Mandela passed his 70th birthday in prison. In 1990, the South African government released not only Mandela but all other imprisoned ANC members--and legalized all the political parties they had previously banned.
There's much, much more, of course. But these are the parts I remember best.