The Catechism divides the Ten Commandments into two tables, because Moses received the commandments on two tables (or tablets).
The summary of the First Table is: “Thou shalt love the Lord thy God with all thy heart and with all thy soul and with all thy mind.” Matt. 22:37.
The summary of the Second Table is: “Thou shalt love thy neighbor as thyself.” Matt. 22:39.
Matt. 22:40: “On these two commandments hang all the Law and the Prophets.