Chapter 18 — Part II: The Sacraments — The Holy Eucharist
Section 172. Distinction of Sacrament and Sacrifice — They should teach, then, in the first place, that the Eucharist was instituted by Christ for two purposes: one, that it might be the heavenly food of our souls, enabling us to support and preserve spiritual life; and the other, that the Church might have a perpetual Sacrifice, by which our sins might be expiated, and our heavenly Father, oftentimes grievously offended by our crimes, might be turned away from wrath to mercy, from the severity of just chastisement to clemency. Of this thing we may observe a type and resemblance in the Paschal lamb, which was wont to be offered and eaten by the children of Israel as a sacrament and a sacrifice.