The Wealth of Nations by Part 4 Chapter 7 Page 96

arbitrary, where it is usual for the magistrate to intermeddle even in the management of the private property of individuals, and to send them, perhaps, a lettre de cachet if they do not manage it according to his liking, it is much easier for him to give some protection to the slave; and common humanity naturally disposes him to do so. The protection of the magistrate renders the slave less contemptible in the eyes of his master, who is thereby induced to consider him with more regard, and to treat him with more gentleness. Gentle usage renders the slave not only more faithful, but more intelligent, and therefore, upon a double account, more useful.

He approaches more to the condition of a free servant, and may possess some degree of integrity and attachment to his master’s interest, virtues which frequently belong