He reflected that Tuesday's inauguration ceremony would take place on the same mall where many thousands gathered in 1963 to hear Martin Luther King's so-called "I Have A Dream" speech - in which he foresaw a day when people would be judged not by the colour of their skin.
"We resolve that as we walk, we must walk together. And as we go forward in the work of renewing the promise of this nation, let's remember King's lesson - that our separate dreams are really one," Mr Obama said.
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