Catechism of the Catholic Church §1753 — excerpt
A good intention (for example, that of helping one's neighbor) does not make behavior that is intrinsically disordered, such as lying and calumny, good or just.
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.