How is president lincoln's gettysburg address and dr. martin luther king, jr.'s "i have a dream" speech different?

Lincolns Gettysburg address was given to memorialize the battle of Gettysburg and the soldiers who fought in it, as well as remind the nation as to the reason they were fighting (the civil war). I have a dream on the other hand was given by Martin Luther King Jr. on the topic of civil rights, his "dream" that he talks about is his vision for civil rights in America.