Q.49: What does the preface to the Ten Commandments teach us?
A. The preface to the Ten Commandments teaches us that because God is the Lord, and our God and Redeemer, therefore we are bound to keep all His commandments.
That he would grant unto us, that we being delivered out of the hand of our enemies might serve him without fear, in holiness and righteousness before him, all the days of our life. Luke 1:74-75
But as he which has called you is holy, so be ye holy in all manner of conversation; because it is written, be ye holy; for I am holy. And if ye call on the Father, who without respect of persons judges according to every man’s work, pass the time of your sojourning here in fear: forasmuch as ye know that ye were not redeemed with corruptible things, as silver and gold, from your vain conversation received by tradition from your fathers; but with the precious blood of Christ, as of a lamb without blemish and without spot. 1 Peter 1:15-19