Describe symbolism in Lincoln at Gettysburg: The Words that Remade America by Garry Wills

In Chapter Five, the author states, Lincoln does not argue law or history as Daniel Webster did. He makes history. He does not come to present a theory, but to impose a symbol, one tested in experience and appealing to national values, with an emotional urgency entirely expressed in calm abstractions (fire in ice). He came to change the world, to effect an intellectual revolution. No other words could have done it. The miracle is that these words did. ... At Gettysburg, he wove a spell that has not, yet been broken.