Chapter 39 — Part IV: Prayer — The Fifth Petition: Forgive Us Our Trespasses as We Forgive Those Who Trespass Against Us
Section 26. Here we ask pardon not only for our venial offences, for which pardon may most easily be obtained, but also for grievous and mortal sins. With regard to grave sins, however, this Petition cannot procure forgiveness unless it derive that efficacy from the Sacrament of Penance, received, as we have already said, either actually or at least in desire.'