Shorter Catechism Q. 44. What doth the preface to the ten commandments teach us? A. 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.
Commentary: The opening words of the decalogue teach us two reasons we should keep the commandments. The first reason is that God is the Lord. He is the creator and ruler of the universe. We are all under his authority and therefore, we are all “bound to keep all his commandments.” This is true for everyone. It doesn’t matter if you don’t believe in God, ignore him, or hate him. It doesn’t matter if you are a Christian or not. A person’s beliefs and actions do not change the objective truth that we must obey God because he is the Lord.
The second reason pertains to Christians. We are bound to keep God’s commandments because God is “our God, and redeemer.” We were bought with a price (1 Cor. 6:20), we were ransomed from our futile ways with the precious blood of Christ (1 Peter 1:18-19), so that we might serve God without fear, in holiness and righteousness (Luke 1:74-75). We are, therefore, not our own. Nor are we Satan’s. We are God’s. We are his liberated children, and as such “we are bound to keep all his commandments.”