Catechism of the Catholic Church §2142 — excerpt
The second commandment prescribes respect for the Lord's name. Like the first commandment, it belongs to the virtue of religion and more particularly it governs our use of speech in sacred matters.
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.