The opening of King's speech uses metaphors to compare the promises of freedom made in the Declaration of Independence, the Constitution and the Emancipation Proclamation and the failure of these documents to procure those freedoms for all. He then turns to a metaphor familiar to all--the weather.
Quote: "This sweltering summer of the Negro's legitimate discontent will not pass until there is an invigorating autumn of freedom and equality."
Metaphor: King compares the legitimate anger of African-Americans to sweltering summer heat and freedom and equality to invigorating autumn.
Analysis: Anyone who's visited Washington D.C. in August has a keen understanding of what a "sweltering summer" produces--frustration, suffering, restlessness and a longing for relief. The hundreds of thousands in attendance would have clearly understood the implications of the need for relief from a sweltering summer day and the need for legislation that would procure rights for minorities; relief that began to arrive with the Civil Rights Act of 1964.
