Catechism of the Catholic Church §2475 — excerpt
Christ's disciples have "put on the new man, created after the likeness of God in true righteousness and holiness." By "putting away falsehood," they are to "put away all malice and all guile and insincerity and envy and all slander."
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.