Here's Tomas de Mercado, quoted at some length in the book on why private property is superior to common property:
because people love most those things that belong to them. If I love God, it is my God, Creator and Savior whom I love. If I love him who engendered me, it is my father whom I love. If a father loves his children, it is because they are his. If a wife loves her husband it is because he belongs to her and vice versa. . . . And if I love a friend it is my friend or my parent or my neighbor. If I desire the common good, it is for the benefit of my religion or my country or my republic. Love always involves the word mine, and the concept of property is basic to love's nature and essence.
Chaufen then writes:
Due to original sin, there is so much covetousness that "the whole world is insufficient for one person, much less for everyone." Realizing that economic goods are scarce, Mercado espoused private property as an efficient method of reducing-if not overcoming-scarcity.
Again quoting Mercado:
We cannot find a person who does not favor his own interests or who does not prefer to furnish his home rather than that of the republic. We can see that privately owned property flourishes, while city- and council-owned property suffers from inadequate care and worse management. In this regard Aristotle states that the pleasure that a man feels while working at his own business is inevitable. It is not easy to explain how important it is for a man to know that he is the owner of the thing he produces. On the other hand, people treat common enterprises with great indifference. ... After man's loss of innocence, it becomes necessary for each individual to share in the things of this world, in real estate or moveable riches. . . . If universal love will not induce people to take care of things, private interest will. Hence, privately owned goods will multiply. Had they remained in common possession, the opposite would be true.