Roman Catechism 17.33

Chapter 17 — Part II: The Sacraments — Confirmation

Section 33. Dispositions For Receiving Confirmation — From this, therefore, it follows that persons of mature age, who are to be confirmed, must, if they desire to obtain the grace and gifts of this Sacrament, not only bring with them faith and piety, but also grieve from their hearts for the serious sins which they have committed.