Catechism of the Catholic Church §1770 — excerpt
Moral perfection consists in man's being moved to the good not by his will alone, but also by his sensitive appetite, as in the words of the psalm: "My heart and flesh sing for joy to the living God."
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.