Catechism of the Catholic Church §1691 — excerpt
"Christian, recognize your dignity and, now that you share in God's own nature, do not return to your former base condition by sinning. Remember who is your head and of whose body you are a member.
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.
Also cites: St. Leo the Great Sermo 22 in nat. Dom., 3: PL 54, 192C