Rerum Novarum Excerpt I -
This part talks about socialism and why the socialist way is not correct:

"4. To remedy these wrongs the socialists, working on the poor man's envy of the rich, are striving to do away with private property, and contend that individual possessions should become the common property of all, to be administered by the State or by municipal bodies. They hold that by thus transferring property from private individuals to the community, the present mischievous state of things will be set to rights, inasmuch as each citizen will then get his fair share of whatever there is to enjoy. But their contentions are so clearly powerless to end the controversy that were they carried into effect the working man himself would be among the first to suffer. They are, moreover, emphatically unjust, for they would rob the lawful possessor, distort the functions of the State, and create utter confusion in the community.

5. It is surely undeniable that, when a man engages in remunerative labor, the impelling reason and motive of his work is to obtain property, and thereafter to hold it as his very own. If one man hires out to another his strength or skill, he does so for the purpose of receiving in return what is necessary for the satisfaction of his needs; he therefore expressly intends to acquire a right full and real, not only to the remuneration, but also to the disposal of such remuneration, just as he pleases. Thus, if he lives sparingly, saves money, and, for greater security, invests his savings in land, the land, in such case, is only his wages under another form; and, consequently, a working man's little estate thus purchased should be as completely at his full disposal as are the wages he receives for his labor. But it is precisely in such power of disposal that ownership obtains, whether the property consist of land or chattels. Socialists, therefore, by endeavoring to transfer the possessions of individuals to the community at large, strike at the interests of every wage-earner, since they would deprive him of the liberty of disposing of his wages, and thereby of all hope and possibility of increasing his resources and of bettering his condition in life.

6. What is of far greater moment, however, is the fact that the remedy they propose is manifestly against justice. For, every man has by nature the right to possess property as his own. This is one of the chief points of distinction between man and the animal creation, for the brute has no power of self direction, but is governed by two main instincts, which keep his powers on the alert, impel him to develop them in a fitting manner, and stimulate and determine him to action without any power of choice. One of these instincts is self preservation, the other the propagation of the species. Both can attain their purpose by means of things which lie within range; beyond their verge the brute creation cannot go, for they are moved to action by their senses only, and in the special direction which these suggest. But with man it is wholly different. He possesses, on the one hand, the full perfection of the animal being, and hence enjoys at least as much as the rest of the animal kind, the fruition of things material. But animal nature, however perfect, is far from representing the human being in its completeness, and is in truth but humanity's humble handmaid, made to serve and to obey. It is the mind, or reason, which is the predominant element in us who are human creatures; it is this which renders a human being human, and distinguishes him essentially from the brute. And on this very account - that man alone among the animal creation is endowed with reason - it must be within his right to possess things not merely for temporary and momentary use, as other living things do, but to have and to hold them in stable and permanent possession; he must have not only things that perish in the use, but those also which, though they have been reduced into use, continue for further use in after time. "