Chapter 12 — Part I: The Creed — Article X: The Forgiveness of Sins
Section 17. The Great Evil From Which Forgiveness Delivers Man — For whoever offends God, even by one mortal sin, instantly forfeits whatever merits he may have previously acquired through the sufferings and death of Christ, and is entirely shut out from the gate of heaven which, when already closed, was thrown open to all by the Redeemer's Passion. When we reflect on this, the thought of our misery must fill us with deep anxiety. But if we turn our attention to this admirable power with which God has invested His Church; and, in the firm belief of this Article, feel convinced that to every sinner is offered the means of recovering, with the assistance of divine grace, his former dignity, we must exult with exceeding joy and gladness, and must offer immortal thanks to God.