What four metaphors does Dr. Martin Luther King, Jr. use?

I am assuming that your question is about King's famous "I Have a Dream" speech, delivered August 28, 1963.  King used more than four metaphors in this speech, but I will discuss two for you, and perhaps you can find two more yourself. Remember, a metaphor is a way of expressing something in terms of something else, so that if I say, "My life is all sunshine," I am expressing that my life is filled...

I am assuming that your question is about King's famous "I Have a Dream" speech, delivered August 28, 1963.  King used more than four metaphors in this speech, but I will discuss two for you, and perhaps you can find two more yourself. Remember, a metaphor is a way of expressing something in terms of something else, so that if I say, "My life is all sunshine," I am expressing that my life is filled with warmth and light and probably happiness.

One of the metaphors King uses is a monetary metaphor, introduced by saying he and other African-Americans were at the capital to "cash a check," (para. 4.), a kind of "promissory note" (para. 4) promised to all Americans in the Declaration of Independence. But, King argues, this was "bad check, a check which has come back marked 'insufficient funds'" (para. 4).  King says he refuses to believe that the check is bad, so the time has come to cash it, demanding "the riches of freedom and the security of justice" (para. 5). Thus, a check is a metaphor for our inalienable rights, rights that have been denied to African-Americans, but that should be available upon demand for all. 

King also uses geographical metaphors, specifically valleys and mountains. He refers to African-Americans being in "the valley of despair" (para. 15), and exhorts American to "rise up" (para. 17), to bring equality to all.  Sometimes his geographical metaphor switches a bit, for example, to mean he wants even ground for everyone, for example, saying this,

I have a dream that one day every valley shall be exalted, and every hill and mountain shall be made low, the rough places will be made plain.... (para. 24).

In fact, we have a metaphor we use today that is very similar and not nearly as poetic, when we say we want a level playing field for everyone.  There are other geographical metaphors, too, in this speech.

Metaphors are so important because they allow us to visualize ideas in a concrete way, and King was particularly good at this.  Look for other metaphors in the speech, for example, some weather metaphors and a palace metaphor. This is a great speech to practice metaphor-spotting skills!