Catechism of the Catholic Church

The word "Decalogue" means literally "ten words." God revealed these "ten words" to his people on the holy mountain. They were written "with the finger of God," unlike the other commandments written by Moses. They are pre-eminently the words of God. They are handed on to us in the books of Exodus and Deuteronomy. Beginning with the Old Testament, the sacred books refer to the "ten words," but it is in the New Covenant in Jesus Christ that their full meaning will be revealed. (700, 62)