Chapter 5 is titled "On Property" and is the basic framework of Locke's property theory.
Despite some funny definitions and some odd omissions, he creates a few rules for property both inside and outside of society. Then, he uses those rules to make a few interesting arguments about property, and especially its accumulation.
It's also worth remembering that Locke was writing about 80 years before Adam Smith's "Wealth of Nations" and 100 more years before the marginal revolution.