Speaking during the march on Washington, D.C. in 1963, Dr. Martin Luther King, Jr. claims that African Americans have come to the nation's capital to cash "a promissory note," a note that must be honored or there will be no tranquility in America.

This "promissory note" is a promise written into the Constitution that all men are guaranteed the "unalienable rights of life, liberty, and the pursuit of happiness." King contends that even though his people were freed by the Emancipation Proclamation, they are still not afforded true freedom because there is a lack of opportunity under segregation and police brutality. King contends that "[T]here will be neither rest nor tranquility in America until the Negro is granted his citizenship rights."

At the same time, Dr. King urges his people not to resort to acts of hatred. He further urges them to conduct their struggle with "dignity and discipline," and to avoid all physical violence.

Dr. Martin Luther King ends his speech with his famous words "I have a dream." He speaks of a new vision for America in which the people of his race will be afforded equal opportunities and equal justice under the precept in the Constitution that "all men are created equal." With this dream and "faith" that the "promissory note" will be honored, Dr. King encourages his people to continue to pursue the changes necessary in America.

Martin Luther King's “I Have a Dream” speech is essentially a persuasive speech, delivered in 1963 during the March on Washington.

People giving persuasive essays and speeches intend to convince their audiences to agree with their position on a certain issue. This “position” is often referred to as a claim. To be effective, a claim has to be well-expressed and credible. Achieving this credibility depends on several things, including the speaker's reputation and how well his or her claim is supported.

At about 16 minutes, King's speech was fairly long. To find his claim in that much text, you have to find the sentence expressing King's central message. What does he say that, if you stripped away all the rest of the text, still makes his main point?

I think the sentence that does the best job of this is the first sentence of the third paragraph:

But one hundred years later, the Negro still is not free.

Everything else is in the speech is used to support this claim. King goes on to use many different rhetorical and oratorical devices; he gives many different examples and cites many different facts, but all of it is intended to show how African-Americans still suffered the effects of racial prejudice in 1963.