From Leo XIII’s encyclical Humanum genus, of April 20, 1884

Just as a perfect condition of the body results from the conjunction and composition of its various members, which, though differing in form and purpose, make, by their union and the distribution of each one to its proper place, a combination beautiful to behold, firm in strength, and necessary for use; so, in the commonwealth, there is an almost infinite dissimilarity of men, as parts of the whole. If they are to be all equal, and each is to follow his own will, the State will appear most deformed; but if, with a distinction of degrees of dignity, of pursuits and employments, all aptly conspire for the common good, they will present a natural image of a well-constituted State.