It is clear that the main tenet of socialism, community of goods, must be utterly rejected, since it only injures those whom it would seem meant to benefit, is directly contrary to the natural rights of mankind, and would introduce confusion and disorder into the commonweal. The first and most fundamental principle, therefore, if one would undertake to alleviate the condition of the masses, must be the inviolability of private property.
Pope Leo XIIIPeople differ in capacity, skill, health, strength; and unequal fortune is a necessary result of unequal condition. Such inequality is far from being disadvantageous either to individuals or to the community.
Pope Leo XIIINot only, in strict truth, was marriage instituted for the propagation of the human race, but also that the lives of husbands and wives might be made better and happier. This comes about in many ways: by their lightening each other's burdens through mutual help; by constant and faithful love; by having all their possessions in common; and by the heavenly grace which flows from the sacrament.
Pope Leo XIIIThe sacred rites, although not instituted specifically for proving the truth of the dogmas of the Catholic Faith incontrovertibly, are effectively the living voice of Catholic Truth, the oft-sounded expression of it. For that very reason the true Church of Christ, even as she shows great zeal to guard inviolate those forms of divine worship - since they are hallowed and are not to be changed - sometimes grants or permits something novel in the performance of them in certain instances. This she does especially when they are in conformity with their venerable antiquity.
Pope Leo XIIIWith reason, then, the common opinion of mankind, little affected by the few dissentients who have contended for the opposite view, has found in the careful study of nature, and in the laws of nature, the foundations of the division of property, and the practice of all ages has consecrated the principle of private ownership, as being pre-eminently in conformity with human nature, and as conducing in the most unmistakable manner to the peace and tranquility of human existence.
Pope Leo XIII