Question 48: What is the preface to the ten commandments?
Answer: 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 (Ex. 20:2).
Question 49: What doth the preface to the ten commandments teach us?
Answer: The preface to the ten commandments teacheth us that because God is the Lord, and our God and redeemer, therefore we are bound to keep all his commandments (Luke 1:74, 75; 1 Pet. 1:15-19).