In which line does Dr. King state his purpose? What other seminal US documents does Dr. King cite in his speech?

King
states the purpose of the March on Washington in the third paragraph of his famous speech. He
says that he and the many others who've made this march to the nation's capital have come to
"cash a check". What he means by this is that the civil rights movement is now
demanding the fulfillment of the promise of American freedom as set out in Abraham Lincoln's
Gettysburg Address and the Declaration of Independence.

King invokes
Lincoln's famous speech to remind those millions of people watching at home than the civil
rights movement aren't demanding anything radical, something that might undermine the very
foundations of American government. They are simply demanding what they were promised by Lincoln
a century ago, a promise that was never fulfilled.

King's invocation of the
Declaration of Independence has much the same purpose. He wants to show the world that the civil
rights movement, far from consisting of dangerous radicals, stands firmly in the tradition of
American liberty, a...