Neither are good at providing pithy quotes, but I do know of this one from Aristotle: "Even if the end is the same for an individual and for a city-state, that of the city-state seems at any rate greater and more complete to attain and preserve. For although it is worthy to attain it for only an individual, it is nobler and more divine to do so for a nation or city-state” (EN I.2.1094b7-10) I found a good exposition of that quotes meaning in https://plato.stanford.edu/entries/aristotle-politics/. On Plato, we can look to his Theory of Forms, articulated in many different ways throughout his writings but can generally be summarized as "For any property F, there is exactly one form of F-ness. Things that are F (other than the F) are F by virtue of partaking of the F." In other words, what we call "humanness" comes from the one exact Form of Humanness, and anything we can call a "human" is such by virtue of partaking of Humanness. Though Aristotle rejects Plato's Forms as existing seperately from objects, he still adopts an idea of forms (small f) as meaning all objects of a type are that type by virtue of it onfomring to a form.