According to Roosevelt, why must a “healthy republican (representative) government . . . rest upon individuals”?

Here we are referring to an excerpt of the speech Theodore Roosevelt delivered on September 7, 1903, to an association called New York State Agricultural, in the city of Syracuse, New York. The speech was known as "The Square Deal."
According to Roosevelt, a “healthy republican government must rest upon individuals, not upon classes or sections,” because when it becomes the government of a section or a class it departs from the old American ideal.
Roosevelt invited people to act together when he expressed: "we must act upon the motto of all for each and each for all."