Catechism of the Catholic Church §2727 — excerpt
We must also face the fact that certain attitudes deriving from the mentality of "this present world" can penetrate our lives if we are not vigilant.
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.