Chapter 18 — Part II: The Sacraments — The Holy Eucharist
Section 125. The Eucharist Strengthens Against Temptation — There is, furthermore, such a power in the sacred mysteries as to preserve us pure and unsullied from sin, keep us safe from the assaults of temptation, and, as by some heavenly medicine, prepare the soul against the easy approach and infection of virulent and deadly disease. Hence, as St. Cyprian records, when the faithful were formerly hurried in multitudes by tyrants to torments and death, because they confessed the name of Christ, it was an ancient usage in the Catholic Church to give them, by the hands of the Bishop, the Sacrament of the body and blood of our Lord, lest perhaps overcome by the severity of their sufferings, they should fail in the fight for salvation.