Leviticus 19 deals with social relationships within the community, and these commandments are seen as major regulators of community relationships. God gives all of these laws with a common thought in mind: "You shall be holy, for I the LORD your God am holy." These laws are given because the Lawgiver is God (see verses 4, 10, 12, etc.).
They are not primarily statements of authority ("Do this because I tell you"), though some of this is included, but statements of the relationship between the Lawgiver and His law. The laws reflect His nature. The law is what it is because God is what He is. Therefore, if we want to be like God, we will imitate Him by obeying His laws in their physical and spiritual applications.
John W. Ritenbaugh
The Fifth Commandment (1997)
Other Forerunner Commentary entries containing Leviticus 19:31: