Leviticus 18:2-4

Speak unto the children of Israel, and say unto them, I am the LORD your God.

I am the Lord your God. This renewed mention of the divine sovereignty over the Israelites was intended to bear particularly on some laws that were widely different from the social customs that obtained both in Egypt and Canaan; because the enormities which the laws enumerated in this chapter were intended to put down were freely practiced or publicly sanctioned in both of those countries; and, indeed, the extermination of the ancient Canaanites is described as owing to the abominations with which they had polluted the land.