Catechism of the Catholic Church §1839 — excerpt
The moral virtues grow through education, deliberate acts, and perseverance in struggle. Divine grace purifies and elevates them.
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.