13 That right to property, therefore, which has been proved to belong naturally to individual persons, must in like wise belong to a man in his capacity of head of a family; nay, that right is all the stronger in proportion as the human person receives a wider extension in the family group. It is a most sacred law of nature that a father should provide food and all necessaries for those whom he has begotten; and, similarly, it is natural that he should wish that his children, who carry on, so to speak, and continue his personality, should be by him provided with all that is needful to enable them to keep themselves decently from want and misery amid the uncertainties of this mortal life. Now, in no other way can a father effect this except by the ownership of productive property, which he can transmit to his children by inheritance. A family, no less than a State, is, as We have said, a true society, governed by an authority peculiar to itself, that is to say, by the authority of the father. Provided, therefore, the limits which are prescribed by the very purposes for which it exists be not transgressed, the family has at least equal rights with the State in the choice and pursuit of the things needful to its preservation and its just liberty. We say, "at least equal rights"; for, inasmuch as the domestic household is antecedent, as well in idea as in fact, to the gathering of men into a community, the family must necessarily have rights and duties which are prior to those of the community, and founded more immediately in nature. If the citizens, if the families on entering into association and fellowship, were to experience hindrance in a commonwealth instead of help, and were to find their rights attacked instead of being upheld, society would rightly be an object of detestation rather than of desire.
Source: Rerum Novarum (Vatican.va)