In his 1963-speech “I Have a Dream”, Dr. Martin Luther King Jr. states the purpose of the speech between lines 1-3:
“<em>I am happy to join with you today in what will go down in history as the greatest </em><em>demonstration for freedom in the history of our nation</em>.”
In these lines, MLK is giving the audience the reason for their presence in that March of August 28th: the freedom of African-Americans.
In order to support his speech, MLK cites some U.S seminal documents. Some of them are the Emancipation Proclamation in line 5:
“<em>Five score years ago, a great American, in whose symbolic shadow we stand today, signed the </em><em>Emancipation Proclamati</em><em>on.</em>”
Also, in subsequent lines (line 20-22), he cites the U.S. Constitution and the Declaration of Independence.
“<em>In a sense we’ve come to our nation’s capital to cash a check. When the architects of our republic wrote the magnificent words of the </em><em>Constituti</em><em>on and the </em><em>Declaration of Independence</em>.”