Chapter 19 — Part II: The Sacraments — Penance
Section 158. Source of the Efficacy of Satisfactory Works — Of the great efficacy of penance we may form some idea, if we reflect that it arises entirely from the merits of the Passion of Christ our Lord. It is His Passion that imparts to our good actions two greatest advantages: the first, that we may merit the rewards of eternal glory, so that a cup of cold water given in His name shall not be without its reward; the second, that we may be able to satisfy for our sins.