He's just making that shit up as he goes along
A remarkable fact of which I was unaware is that the last third of the speech — the part about the dream — was extemporized by King. He had a text, completed the night before. But as he was addressing the crowd, protesting the indignities and brutalities suffered by blacks, he put the prepared speech aside, paused for a moment and then introduced an entirely new theme.
“I still have a dream,” he said. “It is a dream deeply rooted in the American dream.
“I have a dream that one day this nation will rise up and live out the true meaning of its creed: ‘We hold these truths to be self-evident, that all men are created equal.’ ”
With that quotation from the Declaration of Independence, King made clear that his vision of the future for black Americans was for them to be part of the larger society, not embittered opponents of it. He reiterated the point a few minutes later. Faith in his dream, he said, will bring a day “when all of God’s children will be able to sing with new meaning, ‘My country, ’tis of thee, sweet land of liberty, of thee I sing.’ ” Those “I have a dream” paragraphs still bring tears to my eyes.