What is an example of a metaphor in Dr. Martin Luther King, Jr.'s speech "I Have a Dream?"

Martin Luther King Jr.
employs metaphorical language when he says,

Five score
years ago a great American in whose symbolic shadow we stand today signed the Emancipation
Proclamation.

King refers to the figurative shadow of
President Abraham Lincoln and the literal shadow of the monument that memorializes him in this
line.To say that someone stands in another person's shadow means that the person with the shadow
has had a major influence or significant impact: we might say that they cast a long
shadow.King alludes to the fact that Lincoln had a big influence on the granting of
rights to black people in this country (since he is the president responsible for ending
slavery).

King then refers to the Emancipation Proclamation as "a great
beacon light of hope to millions of slaves who had been seared in the flames of withering
injustice."This line contains two metaphors: first, the decree is compared to a beacon,
like a lighthouse that shines and gives hope to sailors because the decree...