Albert Barnes Commentary Leviticus 18:2

"Speak unto the children of Israel, and say unto them, I am Jehovah your God." — Leviticus 18:2 (ASV)

I am, the Lord your God — The frequent repetition of this formula in these parts of the Law may be intended to remind the Israelites of their covenant with Yahweh in connection with the common affairs of life, where they might be tempted to look at legal restrictions in a mere secular light.