It is in the very midst of revelation that the transition is made from the theme of Deliverance to Identity. I believe that this was to enhance the impact and authority of the commandments. They flowed from the heart of God in an atmosphere of holy fear. They are not to be taken lightly, as they are now taught, in Sunday School classes for children. God was not merely trying to overawe people with His Presence, He was trying to convey to them a message of vital and permanent importance.
We must remember that the Israelites were a blank slate, they were coming out of a moral vacuum in Egypt, they had no laws higher than personal survival. Prolonged slavery reduces men to barbarians, suppressing culture, education, morality. Ex 20 is Gen 1:26 revisited: "Let us make man in our image, after our likeness." Only here we are not dealing with the physical creation of man, but with the construction of a society "ex nihilo." These commandments were the preconditions for the new corporate Adam to walk in fellowship with God in the new Eden of the Promised Land. More than this, they were also collectively the definition of the "new man," distinct from both Egyptians and Canaanites. Conduct and character were now a part of the Covenant. An outsider should be able to tell from a man's behavior, not just from his penis, that he was an Israelite.