What is the preface to the Ten Commandments?

Shorter CatechismQ 43. What is the preface to the ten commandments?A. The preface to the Ten Commandments is in these words, I am the LORD thy God, which have brought thee out of the land of Egypt, out of the house of bondage.1Exodus 20:2 “I am the Lord your God, who brought you out of the land of Egypt, out of the house of slavery. Deuteronomy 5:6 “‘I am the Lord your God, who brought you out of the land of Egypt, out of the house of slavery. (ESV)