Hey there!
Martin Luther King's iconic "I Have a Dream" speech is full of allusions.Let's look at a few:
1.) "Five score years ago, a great American, in whose symbolic shadow we stand today, signed the Emancipation Proclamation"
Dr. King's speech (1963) was made 100 years after Lincoln's Emancipation Proclamation (1863) that freed all slaves in rebel territories. King salutes Lincoln's contribution to the fight against discrimination. He literally and figuratively stands in Lincoln's "shadow," as he is giving the speech in front of the Lincoln monument and he is continuing the fight that Lincoln played such a large role in
2.) "When the architects of our republic wrote the magnificent words of the Constitution and the Declaration of Independence, they were signing a promissory note to which every American was to fall, heir.... Instead of honoring this sacred obligation, America has given the Negro people a bad check"
King references the document which proclaims that "All men are created equal... with certain unalienable rights." He then proceeds to decry the denial of these rights and this equality by the segregation and racism that the African-American community has faced since the founding of the nation (and still faces today)
I hope this helps!