The diversity in the faculties of men, from which the rights of property originate, is not less an insuperable obstacle to a uniformity of interests. The protection of these faculties is the first object of government. From the protection of different and unequal faculties of acquiring property, the possession of different degrees and kinds of property immediately results.

Madison, James. "No. 47: Complete separation of powers not required.--Madison." The Federalist: A Commentary on the Constitution of the United States, edited by Robert Scigliano. The Modern Library, 2001.

The Constitution of the United States. The Constitution of the United States and The Declaration of Independence. Written by Delegates of The Constitutional Convention. Racehorse, 2016, amend. 2.

Engels, Frederick. "Anti-During." Karl Marx, Frederick Engels: Collected Works. Vol. 25, Int Pub Co Inc, 1987, pt. 3, ch. 2.