Roman Catechism 32.23

Chapter 32 — Part III: The Decalogue — The Ninth and Tenth Commandments

Section 23. "Nor His Ox, Nor His Ass' — The words that follow, nor his ox, nor his ass, teach us that not only is it unlawful to desire things of greater value, such as a house, rank, glory, because they belong to others; but also things of little value, whatever they may be, animate or inanimate.