This organization of the first and second commandments overlooks the fact that verse 2 seems to function as an introduction to the commandments. In fact, it is rather surprising that it is interpreted as a commandment because it lacks the imperative force or tone present in the other commandments. The theological significance of the short historical prologue recorded in verse 2 tends to set it apart from the first commandment. It states the source of this particular law and the historical and theological relation that already existed between this Being and the Israelites. The clear implication is that the demands of the law are preceded by God's gracious act of redemption on behalf of His enslaved people.
Grace comes before law.
Obedience to this divine law is a response of gratitude from loving hearts to the Lord for the redemption already performed on behalf of His people. Verse 2 is an extremely important introduction to the Decalogue. There is a third way of grouping the Ten Commandments, usually followed by Catholics and Lutherans. According to this interpretation, the first commandment is recorded in verses 2-6 and includes the oneness of God and His exclusive worship. The second commandment is against false oaths, and the third is the Sabbath.