Roman Catechism 19.97

Chapter 19 — Part II: The Sacraments — Penance

Section 97. This doctrine the pastors should teach as defined by the holy Council of Trent, and handed down by the uniform doctrine of the Catholic Church. An attentive perusal of the Fathers will present passages throughout their works, proving in the clearest terms that this Sacrament was instituted by our Lord, and that the law of sacramental confession, which, from the Greek, they call exomologesis, and exagoreusis, is to be received as true Gospel teaching.