In a recent article, I discussed the most famous argument in Federalist No. 10, which is itself the most famous of “The Federalist Papers”:
The smaller the society, the fewer probably will be the distinct parties and interests composing it … the more easily will they concert and execute their plans of oppression … Extend the sphere, and you take in a greater variety of parties and interests; you make it less probable that a majority of the whole will … invade the rights of other citizens. — James Madison
Federalist 10, and this argument specifically, have generated a mountain of scholarly writings and commentary for the past century. As virtually every political pundit has chimed in, you have almost certainly read discussions of No. 10 before this.