11 With 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 tranquillity of human existence. The same principle is confirmed and enforced by the civil laws-laws which, so long as they are just, derive from the law of nature their binding force. The authority of the divine law adds its sanction, forbidding us in severest terms even to covet that which is another's: "Thou shalt not covet thy neighbour's wife; nor his house, nor his field, nor his man-servant, nor his maid-servant, nor his ox, nor his ass, nor anything that is his."(2)
Source: Rerum Novarum (Vatican.va)