Charles Ellicott Commentary Exodus 20:2

"I am Jehovah thy God, who brought thee out of the land of Egypt, out of the house of bondage." — Exodus 20:2 (ASV)

I am the Lord your God. —The binding nature of commands upon the conscience depends upon the authority of the person who issues them. So that there might be no dispute as to what the authority was in the case of the Decalogue, God prefaced the commands themselves with this distinct statement. Regardless of who communicated them (see the first Note on Exodus 20:1), they were the commands of Jehovah Himself.

Which have brought you 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.