Roman Catechism 15.51

Chapter 15 — Part II: The Sacraments — Introduction on the Sacraments in General

Section 51. But if we consider the dignity of the Sacraments, the Eucharist, for holiness and for the number and greatness of its mysteries, is far superior to all the rest. These, however, are matters which will be more easily understood, when we come to explain, in its proper place, what regards each of the Sacraments.