Mandela made two particularly well-known speeches during his anti-apartheid struggle in the 50s and 60s.
"No Easy Walk to Freedom" (text) is a 4553-word speech by Mandela read to the African National Congress party in 1953. It contextualizes the actions of South Africans from all walks of life and all races who participated in the Campaign for the Defiance of the Unjust Laws. Mandela talks to how these people sacrificed their jobs and elected to go to jail for the cause, and this bound them together and voiced their opposition to the unjust government in office. It talks about the "Suppression of Communism" and "Public Safety" Acts that allow the government to imprison anyone, even for calling on another person to "defy", and allowed the government to use marshal law against protesters. It lists the people who have been charged under these laws.
There are several sections of normal political rhetoric about social and economic grievances and (in this case racist) policies unfair to his constituency. He lists orders to his supporters to publicize and support the Congress. He instructs them that if they can't meet publicly (because of the legal prohibition), they should meet anywhere else, in their factories or on buses.
He blames on the branch authorities the less-than-desirable members of his party, makes note of enemies within the ranks of the party, detailing some who have been found, and stating that the others have not been found yet. He then states that those who are "friends of the people' are willing to make the sacrifices (life and death) for his party, and enemies are recognized by their unwillingness to sacrifice. He points out that "almost all the people who oppose the "M" Plan are people who have consistently refused to respond when sacrifices are called for, and whose political background leaves much to be desired. These shade characters by means of flattery, bribes and corruption, win the support of the weak-willed and politically backward individuals, detach them from Congress and use them in their own interests." After rhetoric to do with racism and universal rights, he speaks of one of the oppositions facing his party:
"We are exiled from our own people for we have uncompromisingly resisted the efforts of imperialist America and her satellites to drag the world into the rule of violence and brutal force, into the rule of the napalm, hydrogen and the cobalt bombs where millions of people will be wiped out to satisfy the criminal and greedy appetites of the imperial powers. We have been gagged because we have emphatically and openly condemned the criminal attacks by the imperialists against the people of Malaya, Vietnam, Indonesia, Tunisia and Tanganyika and called upon our people to identify themselves unreservedly with the cause of world peace and to fight against the war policies of America and her satellites...."
He then lists some of the specific outrages committed on people in these war-torn regions and states that "We are prisoners in our own country because we dared to raise our voices against these horrible atrocities and because we expressed our solidarity with the cause of the Kenya people."
He then quotes Nehru to the effect that people's desires will come after difficult tribulations, and closes:
"Dangers and difficulties have not deterred us in the past, they will not frighten us now. But we must be prepared for them like men in business who do not waste energy in vain talk and idle action. The way of preparation for action lies in our rooting out all impurity and indiscipline from our organisation and making it the bright and shining instrument that will cleave its way to Africa's freedom."
"I am Prepared to Die" (text) was a 14326-word speech recited by Mandela during his 1963 trial for sabotage and attempting to overthrow the state. In 1963 ten ANC leaders (including Mandela, who was serving a 5 year sentence for incitement to strike and leaving the country illegally) were arrested and charged. It was generally assumed that state would move for the death penalty, and all defendants plead guilty. Mandela believed he would likely receive the death sentence, and for this reason Mandela retained the final, "I am prepared to die" statement despite his lawyers advice, although Mandela added, "if needs be."
Mandela prepared the speech about South African legal injustice, aimed at the international audience, receiving aid from a writer and a journalist (who judged the delivery of the speech to be "most... effective" and "hesitant, boring"), and took as example Castro's 4-hour long "History Will Absolve Me" speech (1953) delivered at Castro's sentencing for charges related to violent revolutionary acts.
The first third explains the rationale and contextualizes the motivation for finally forming a wing of the ANC that uses violence (sabotage). Mandela then speaks to separating the ANC's violent wing and their directives from violent acts committed by other groups. He talks about how, after black violent acts, whites became more reactionary, and whites and blacks became more separated in the struggle which threatened to become a racial civil war. At this point, the white government threatened blacks committing sabotage with death, necessitating--Mandela says--stepping up the level of ANC violence from sabotage to terrorism. Mandela then talks about his tour of Africa, his preparation for guerrilla war, various false charges by the state. He then talks about the ideals and political goals of the ANC, distinguishes the ANC from the Communist Party and explains their inter-relationship. Mandela states his own political beliefs, and speaks praisingly of British and American political institutions. Mandela explains his connections with communism and Communists, details the funding of the ANC, describes the South African economy and labor conditions and the effects of poverty, and closes stating that Apartheid is the reason for these ills, and that he is committed to ending racial segregation.