I am the Lord thy God. — The binding nature of commands upon the conscience depends upon the authority of the person who issues them. That there might be no dispute as to what the authority was in the case of the Decalogue, God prefaced the commands themselves by this distinct statement. By whomsoever they were communicated (see the first Note on Exodus 20:1), they were the commands of Jehovah Himself.
Which have brought thee out of the land of Egypt. — Thus exhibiting at once Almighty power and the tenderest compassion and care. God desires the obedience which springs from love, not fear.