Moses
Exodus 20:2BSB·traditional attribution

“I am the LORD your God, who brought you out of the land of Egypt, out of the house of slavery.

Matthew Henry Presbyterian @wholebiblehenry

Here is, I. The preface of the law-writer, Moses: God spoke all these words, Exo 20:1. The law of the ten commandments is, 1. A law of God's making. They are enjoined by the infinite eternal Majesty of heaven and earth. And where the word of the King of kings is surely there is power. 2. It is a law of his own speaking.

Commenting on Exodus 20:1-11

John Gill Reformed Baptist @doctorgill

I am the Lord thy God,.... This verse does not contain the first of these commands, but is a preface to them, showing that God had a right to enact and enjoin the people of Israel laws; and that they were under obligation to attend unto them with reverence, and cheerfully obey them, since he was the Lord, the eternal and immutable Jehovah, the Being...

Jamieson-Fausset-Brown Reformed @jfbcommentary

I am the Lord thy God--This is a preface to the ten commandments--the latter clause being specially applicable to the case of the Israelites, while the former brings it home to all mankind; showing that the reasonableness of the law is founded in their eternal relation as creatures to their Creator, and their mutual relations to each other.